Relaxed threshold for synchronous access in unlicensed spectrum

ABSTRACT

A relaxed threshold for synchronous access in unlicensed spectrum is disclosed. According to the aspects described herein, nodes accessing a shared communication spectrum using a local synchronous access mode may attempt access via a listen before talk (LBT) procedure using a local synchronous energy detection (ED) threshold. The local synchronous ED threshold is relaxed relative to a standard ED threshold otherwise used for access to the shared communication spectrum. The relaxed nature of the local synchronous ED threshold allows local synchronous access nodes a higher probability to gain access to the shared communication channel. To prevent interference with global synchronous access nodes, the global synchronous access nodes are also able to use the relaxed, local synchronous ED threshold as long as it ends the resulting channel occupancy time (COT) at the next local synchronization boundary.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional PatentApplication No. 62/959,667, entitled, “RELAXED THRESHOLD FOR SYNCHRONOUSACCESS IN UNLICENSED SPECTRUM,” filed on Jan. 10, 2020, which isexpressly incorporated by reference herein in its entirety.

BACKGROUND Field

Aspects of the present disclosure relate generally to wirelesscommunication systems, and more particularly, to a relaxed threshold forsynchronous access in unlicensed spectrum.

Background

Wireless communication networks are widely deployed to provide variouscommunication services such as voice, video, packet data, messaging,broadcast, and the like. These wireless networks may be multiple-accessnetworks capable of supporting multiple users by sharing the availablenetwork resources. Such networks, which are usually multiple accessnetworks, support communications for multiple users by sharing theavailable network resources. One example of such a network is theUniversal Terrestrial Radio Access Network (UTRAN). The UTRAN is theradio access network (RAN) defined as a part of the Universal MobileTelecommunications System (UMTS), a third generation (3G) mobile phonetechnology supported by the 3rd Generation Partnership Project (3GPP).Examples of multiple-access network formats include Code DivisionMultiple Access (CDMA) networks, Time Division Multiple Access (TDMA)networks, Frequency Division Multiple Access (FDMA) networks, OrthogonalFDMA (OFDMA) networks, and Single-Carrier FDMA (SC-FDMA) networks.

A wireless communication network may include a number of base stationsor node Bs that can support communication for a number of userequipments (UEs). A UE may communicate with a base station via downlinkand uplink. The downlink (or forward link) refers to the communicationlink from the base station to the UE, and the uplink (or reverse link)refers to the communication link from the UE to the base station.

A base station may transmit data and control information on the downlinkto a UE and/or may receive data and control information on the uplinkfrom the UE. On the downlink, a transmission from the base station mayencounter interference due to transmissions from neighbor base stationsor from other wireless radio frequency (RF) transmitters. On the uplink,a transmission from the UE may encounter interference from uplinktransmissions of other UEs communicating with the neighbor base stationsor from other wireless RF transmitters. This interference may degradeperformance on both the downlink and uplink.

As the demand for mobile broadband access continues to increase, thepossibilities of interference and congested networks grows with more UEsaccessing the long-range wireless communication networks and moreshort-range wireless systems being deployed in communities. Research anddevelopment continue to advance wireless technologies not only to meetthe growing demand for mobile broadband access, but to advance andenhance the user experience with mobile communications.

SUMMARY

In one aspect of the disclosure, a method of wireless communicationincludes selecting, by a first node, to access a shared communicationchannel according to a local synchronous access mode, performing, by thefirst node, a listen before talk (LBT) procedure on the sharedcommunication channel using a local synchronous energy detectionthreshold, wherein the local synchronous energy detection level isrelaxed relative to a standard energy detection level used for access tothe shared communication channel, establishing, by the first node inresponse to success of the LBT procedure, a channel occupancy time (COT)configured by the first node to end at a next synchronization boundarydetermined according to a local synchronous access clock, andtransmitting, by the first node, data on the shared communicationchannel within the COT up to the end at the next synchronizationboundary.

In an additional aspect of the disclosure, a method of wirelesscommunication includes determining, by a first node configured in aglobal synchronous access mode, that one or more neighboring nodesoperate in a local synchronous access mode for access to a sharedcommunication channel, performing, by the first node, an LBT procedureon the shared communication channel using a local synchronous energydetection threshold, wherein the local synchronous energy detectionlevel is relaxed relative to a standard energy detection level used foraccess to the shared communication channel, establishing, by the firstnode in response to success of the LBT procedure, a COT configured bythe first node to end at a next local synchronization boundarydetermined according to a local synchronous access clock, andtransmitting, by the first node, data on the shared communicationchannel within the COT up to the end at the next synchronizationboundary.

In an additional aspect of the disclosure, an apparatus configured forwireless communication includes means for selecting, by a first node, toaccess a shared communication channel according to a local synchronousaccess mode, means for performing, by the first node, an LBT procedureon the shared communication channel using a local synchronous energydetection threshold, wherein the local synchronous energy detectionlevel is relaxed relative to a standard energy detection level used foraccess to the shared communication channel, means for establishing, bythe first node in response to success of the LBT procedure, a COTconfigured by the first node to end at a next synchronization boundarydetermined according to a local synchronous access clock, and means fortransmitting, by the first node, data on the shared communicationchannel within the COT up to the end at the next synchronizationboundary.

In an additional aspect of the disclosure, an apparatus configured forwireless communication includes means for determining, by a first nodeconfigured in a global synchronous access mode, that one or moreneighboring nodes operate in a local synchronous access mode for accessto a shared communication channel, means for performing, by the firstnode, an LBT procedure on the shared communication channel using a localsynchronous energy detection threshold, wherein the local synchronousenergy detection level is relaxed relative to a standard energydetection level used for access to the shared communication channel,means for establishing, by the first node in response to success of theLBT procedure, a COT configured by the first node to end at a next localsynchronization boundary determined according to a local synchronousaccess clock, and means for transmitting, by the first node, data on theshared communication channel within the COT up to the end at the nextsynchronization boundary.

In an additional aspect of the disclosure, a non-transitorycomputer-readable medium having program code recorded thereon. Theprogram code further includes code to select, by a first node, to accessa shared communication channel according to a local synchronous accessmode, code to perform, by the first node, an LBT procedure on the sharedcommunication channel using a local synchronous energy detectionthreshold, wherein the local synchronous energy detection level isrelaxed relative to a standard energy detection level used for access tothe shared communication channel, code to establish, by the first nodein response to success of the LBT procedure, a COT configured by thefirst node to end at a next synchronization boundary determinedaccording to a local synchronous access clock, and code to transmit, bythe first node, data on the shared communication channel within the COTup to the end at the next synchronization boundary.

In an additional aspect of the disclosure, a non-transitorycomputer-readable medium having program code recorded thereon. Theprogram code further includes code to determine, by a first nodeconfigured in a global synchronous access mode, that one or moreneighboring nodes operate in a local synchronous access mode for accessto a shared communication channel, code to perform, by the first node,an LBT procedure on the shared communication channel using a localsynchronous energy detection threshold, wherein the local synchronousenergy detection level is relaxed relative to a standard energydetection level used for access to the shared communication channel,code to establish, by the first node in response to success of the LBTprocedure, a COT configured by the first node to end at a next localsynchronization boundary determined according to a local synchronousaccess clock, and code to transmit, by the first node, data on theshared communication channel within the COT up to the end at the nextsynchronization boundary.

In an additional aspect of the disclosure, an apparatus configured forwireless communication is disclosed. The apparatus includes at least oneprocessor, and a memory coupled to the processor. The processor isconfigured to select, by a first node, to access a shared communicationchannel according to a local synchronous access mode, to perform, by thefirst node, an LBT procedure on the shared communication channel using alocal synchronous energy detection threshold, wherein the localsynchronous energy detection level is relaxed relative to a standardenergy detection level used for access to the shared communicationchannel, to establish, by the first node in response to success of theLBT procedure, a COT configured by the first node to end at a nextsynchronization boundary determined according to a local synchronousaccess clock, and to transmit, by the first node, data on the sharedcommunication channel within the COT up to the end at the nextsynchronization boundary.

In an additional aspect of the disclosure, an apparatus configured forwireless communication is disclosed. The apparatus includes at least oneprocessor, and a memory coupled to the processor. The processor isconfigured to determine, by a first node configured in a globalsynchronous access mode, that one or more neighboring nodes operate in alocal synchronous access mode for access to a shared communicationchannel, to perform, by the first node, an LBT procedure on the sharedcommunication channel using a local synchronous energy detectionthreshold, wherein the local synchronous energy detection level isrelaxed relative to a standard energy detection level used for access tothe shared communication channel, to establish, by the first node inresponse to success of the LBT procedure, a COT configured by the firstnode to end at a next local synchronization boundary determinedaccording to a local synchronous access clock, and to transmit, by thefirst node, data on the shared communication channel within the COT upto the end at the next synchronization boundary.

The foregoing has outlined rather broadly the features and technicaladvantages of examples according to the disclosure in order that thedetailed description that follows may be better understood. Additionalfeatures and advantages will be described hereinafter. The conceptionand specific examples disclosed may be readily utilized as a basis formodifying or designing other structures for carrying out the samepurposes of the present disclosure. Such equivalent constructions do notdepart from the scope of the appended claims. Characteristics of theconcepts disclosed herein, both their organization and method ofoperation, together with associated advantages will be better understoodfrom the following description when considered in connection with theaccompanying figures. Each of the figures is provided for the purpose ofillustration and description, and not as a definition of the limits ofthe claims.

BRIEF DESCRIPTION OF THE DRAWINGS

A further understanding of the nature and advantages of the presentdisclosure may be realized by reference to the following drawings. Inthe appended figures, similar components or features may have the samereference label. Further, various components of the same type may bedistinguished by following the reference label by a dash and a secondlabel that distinguishes among the similar components. If just the firstreference label is used in the specification, the description isapplicable to any one of the similar components having the same firstreference label irrespective of the second reference label.

FIG. 1 is a block diagram illustrating details of a wirelesscommunication system.

FIG. 2 is a block diagram illustrating a design of a base station and aUE configured according to one aspect of the present disclosure.

FIG. 3 is a block diagram illustrating a portion of NR-U network havingoverlapping nodes competing for access to shared communication spectrum.

FIG. 4 is a block diagram illustrating a portion of NR-U networkconfigured to support synchronous communication mode within a sharedcommunication spectrum.

FIG. 5 is a block diagram illustrating a portion of NR-U networkconfigured to support access to a shared communication spectrum usingeither or both asynchronous modes and synchronous modes.

FIG. 6 is a block diagram illustrating a portion of NR-U networkconfigured to support access to a shared communication spectrum usingeither or both asynchronous modes and synchronous modes.

FIG. 7 is a block diagram illustrating example blocks executed toimplement one aspect of the present disclosure.

FIG. 8 is a block diagram illustrating example blocks executed toimplement one aspect of the present disclosure.

FIG. 9 is a block diagram of a portion of NR-U network, having a localsynchronous access node and a global synchronous access node configuredaccording to aspects of the present disclosure.

FIG. 10 is a block diagram illustrating a base station configuredaccording to one aspect of the present disclosure.

FIG. 11 is a block diagram illustrating a UE configured according to oneaspect of the present disclosure.

DETAILED DESCRIPTION

The detailed description set forth below, in connection with theappended drawings, is intended as a description of variousconfigurations and is not intended to limit the scope of the disclosure.Rather, the detailed description includes specific details for thepurpose of providing a thorough understanding of the inventive subjectmatter. It will be apparent to those skilled in the art that thesespecific details are not required in every case and that, in someinstances, well-known structures and components are shown in blockdiagram form for clarity of presentation.

This disclosure relates generally to providing or participating inauthorized shared access between two or more wireless communicationssystems, also referred to as wireless communications networks. Invarious embodiments, the techniques and apparatus may be used forwireless communication networks such as code division multiple access(CDMA) networks, time division multiple access (TDMA) networks,frequency division multiple access (FDMA) networks, orthogonal FDMA(OFDMA) networks, single-carrier FDMA (SC-FDMA) networks, LTE networks,GSM networks, 5^(th) Generation (5G) or new radio (NR) networks, as wellas other communications networks. As described herein, the terms“networks” and “systems” may be used interchangeably.

An OFDMA network may implement a radio technology such as evolved UTRA(E-UTRA), IEEE 802.11, IEEE 802.16, IEEE 802.20, flash-OFDM and thelike. UTRA, E-UTRA, and Global System for Mobile Communications (GSM)are part of universal mobile telecommunication system (UMTS). Inparticular, long term evolution (LTE) is a release of UMTS that usesE-UTRA. UTRA, E-UTRA, GSM, UMTS and LTE are described in documentsprovided from an organization named “3rd Generation Partnership Project”(3GPP), and cdma2000 is described in documents from an organizationnamed “3rd Generation Partnership Project 2” (3GPP2). These variousradio technologies and standards are known or are being developed. Forexample, the 3rd Generation Partnership Project (3GPP) is acollaboration between groups of telecommunications associations thataims to define a globally applicable third generation (3G) mobile phonespecification. 3GPP long term evolution (LTE) is a 3GPP project whichwas aimed at improving the universal mobile telecommunications system(UMTS) mobile phone standard. The 3GPP may define specifications for thenext generation of mobile networks, mobile systems, and mobile devices.The present disclosure is concerned with the evolution of wirelesstechnologies from LTE, 4G, 5G, NR, and beyond with shared access towireless spectrum between networks using a collection of new anddifferent radio access technologies or radio air interfaces.

In particular, 5G networks contemplate diverse deployments, diversespectrum, and diverse services and devices that may be implemented usingan OFDM-based unified, air interface. In order to achieve these goals,further enhancements to LTE and LTE-A are considered in addition todevelopment of the new radio technology for 5G NR networks. The 5G NRwill be capable of scaling to provide coverage (1) to a massive Internetof things (IoTs) with an ultra-high density (e.g., ˜1M nodes/km²),ultra-low complexity (e.g., ˜10s of bits/sec), ultra-low energy (e.g.,˜10+ years of battery life), and deep coverage with the capability toreach challenging locations; (2) including mission-critical control withstrong security to safeguard sensitive personal, financial, orclassified information, ultra-high reliability (e.g., ˜99.9999%reliability), ultra-low latency (e.g., ˜1 ms), and users with wideranges of mobility or lack thereof; and (3) with enhanced mobilebroadband including extreme high capacity (e.g., ˜10 Tbps/km²), extremedata rates (e.g., multi-Gbps rate, 100+ Mbps user experienced rates),and deep awareness with advanced discovery and optimizations.

The 5G NR may be implemented to use optimized OFDM-based waveforms withscalable numerology and transmission time interval (TTI); having acommon, flexible framework to efficiently multiplex services andfeatures with a dynamic, low-latency time division duplex(TDD)/frequency division duplex (FDD) design; and with advanced wirelesstechnologies, such as massive multiple input, multiple output (MIMO),robust millimeter wave (mmWave) transmissions, advanced channel coding,and device-centric mobility. Scalability of the numerology in 5G NR,with scaling of subcarrier spacing, may efficiently address operatingdiverse services across diverse spectrum and diverse deployments. Forexample, in various outdoor and macro coverage deployments of less than3GHz FDD/TDD implementations, subcarrier spacing may occur with 15 kHz,for example over 1, 5, 10, 20 MHz, and the like bandwidth. For othervarious outdoor and small cell coverage deployments of TDD greater than3 GHz, subcarrier spacing may occur with 30 kHz over 80/100 MHzbandwidth. For other various indoor wideband implementations, using aTDD over the unlicensed portion of the 5 GHz band, the subcarrierspacing may occur with 60 kHz over a 160 MHz bandwidth. Finally, forvarious deployments transmitting with mmWave components at a TDD of 28GHz, subcarrier spacing may occur with 120 kHz over a 500 MHz bandwidth.

The scalable numerology of the 5G NR facilitates scalable TTI fordiverse latency and quality of service (QoS) requirements. For example,shorter TTI may be used for low latency and high reliability, whilelonger TTI may be used for higher spectral efficiency. The efficientmultiplexing of long and short TTIs to allow transmissions to start onsymbol boundaries. 5G NR also contemplates a self-contained integratedsubframe design with uplink/downlink scheduling information, data, andacknowledgement in the same subframe. The self-contained integratedsubframe supports communications in unlicensed or contention-basedshared spectrum, adaptive uplink/downlink that may be flexiblyconfigured on a per-cell basis to dynamically switch between uplink anddownlink to meet the current traffic needs.

Various other aspects and features of the disclosure are furtherdescribed below. It should be apparent that the teachings herein may beembodied in a wide variety of forms and that any specific structure,function, or both being disclosed herein is merely representative andnot limiting. Based on the teachings herein one of an ordinary level ofskill in the art should appreciate that an aspect disclosed herein maybe implemented independently of any other aspects and that two or moreof these aspects may be combined in various ways. For example, anapparatus may be implemented or a method may be practiced using anynumber of the aspects set forth herein. In addition, such an apparatusmay be implemented or such a method may be practiced using otherstructure, functionality, or structure and functionality in addition toor other than one or more of the aspects set forth herein. For example,a method may be implemented as part of a system, device, apparatus,and/or as instructions stored on a computer readable medium forexecution on a processor or computer. Furthermore, an aspect maycomprise at least one element of a claim.

FIG. 1 is a block diagram illustrating an example of a wirelesscommunications system 100 that supports allowing nodes accessing ashared communication spectrum using a local synchronous access mode toattempt access via a listen before talk (LBT) procedure using a localsynchronous energy detection (ED) threshold. The local synchronous EDthreshold is relaxed relative to a standard ED threshold otherwise usedfor access to the shared communication spectrum. The relaxed nature ofthe local synchronous ED threshold allows local synchronous access nodesa higher probability to gain access to the shared communication channelin accordance with aspects of the present disclosure. To preventinterference with global synchronous access nodes, the globalsynchronous access nodes are also able to use the relaxed, localsynchronous ED threshold as long as it ends the resulting channeloccupancy time (COT) at the next local synchronization boundary. Thewireless communications system 100 includes base stations 105, UEs 115,and a core network 130. In some examples, the wireless communicationssystem 100 may be a Long Term Evolution (LTE) network, an LTE-Advanced(LTE-A) network, an LTE-A Pro network, or NR network. In some cases,wireless communications system 100 may support enhanced broadbandcommunications, ultra-reliable (e.g., mission critical) communications,low latency communications, or communications with low-cost andlow-complexity devices.

Base stations 105 may wirelessly communicate with UEs 115 via one ormore base station antennas. Base stations 105 described herein mayinclude or may be referred to by those skilled in the art as a basetransceiver station, a radio base station, an access point, a radiotransceiver, a NodeB, an eNodeB (eNB), a next-generation NodeB orgiga-NodeB (either of which may be referred to as a gNB), a Home NodeB,a Home eNodeB, or some other suitable terminology. Wirelesscommunications system 100 may include base stations 105 of differenttypes (e.g., macro or small cell base stations). The UEs 115 describedherein may be able to communicate with various types of base stations105 and network equipment including macro eNBs, small cell eNBs, gNBs,relay base stations, and the like.

Each base station 105 may be associated with a particular geographiccoverage area 110 in which communications with various UEs 115 issupported. Each base station 105 may provide communication coverage fora respective geographic coverage area 110 via communication links 125,and communication links 125 between a base station 105 and a UE 115 mayutilize one or more carriers. Communication links 125 shown in wirelesscommunications system 100 may include uplink transmissions from a UE 115to a base station 105, or downlink transmissions from a base station 105to a UE 115. Downlink transmissions may also be referred to as forwardlink transmissions while uplink transmissions may also be referred to asreverse link transmissions.

The geographic coverage area 110 for a base station 105 may be dividedinto sectors making up a portion of the geographic coverage area 110,and each sector may be associated with a cell. For example, each basestation 105 may provide communication coverage for a macro cell, a smallcell, a hot spot, or other types of cells, or various combinationsthereof. In some examples, a base station 105 may be movable and,therefore, provide communication coverage for a moving geographiccoverage area 110. In some examples, different geographic coverage areas110 associated with different technologies may overlap, and overlappinggeographic coverage areas 110 associated with different technologies maybe supported by the same base station 105 or by different base stations105. The wireless communications system 100 may include, for example, aheterogeneous LTE/LTE-A/LTE-A Pro or NR network in which different typesof base stations 105 provide coverage for various geographic coverageareas 110.

The term “cell” refers to a logical communication entity used forcommunication with a base station 105 (e.g., over a carrier), and may beassociated with an identifier for distinguishing neighboring cells(e.g., a physical cell identifier (PCID), a virtual cell identifier(VCID)) operating via the same or a different carrier. In some examples,a carrier may support multiple cells, and different cells may beconfigured according to different protocol types (e.g., machine-typecommunication (MTC), narrowband Internet-of-things (NB-IoT), enhancedmobile broadband (eMBB), or others) that may provide access fordifferent types of devices. In some cases, the term “cell” may refer toa portion of a geographic coverage area 110 (e.g., a sector) over whichthe logical entity operates.

UEs 115 may be dispersed throughout the wireless communications system100, and each UE 115 may be stationary or mobile. A UE 115 may also bereferred to as a mobile device, a wireless device, a remote device, ahandheld device, or a subscriber device, or some other suitableterminology, where the “device” may also be referred to as a unit, astation, a terminal, or a client. A UE 115 may also be a personalelectronic device such as a cellular phone (UE 115 a), a personaldigital assistant (PDA), a wearable device (UE 115 d), a tabletcomputer, a laptop computer (UE 115 g), or a personal computer. In someexamples, a UE 115 may also refer to a wireless local loop (WLL)station, an Internet-of-things (IoT) device, an Internet-of-everything(IoE) device, an MTC device, or the like, which may be implemented invarious articles such as appliances, vehicles (UE 115 e and UE 115 f),meters (UE 115 b and UE 115 c), or the like.

Some UEs 115, such as MTC or IoT devices, may be low cost or lowcomplexity devices, and may provide for automated communication betweenmachines (e.g., via machine-to-machine (M2M) communication). M2Mcommunication or MTC may refer to data communication technologies thatallow devices to communicate with one another or a base station 105without human intervention. In some examples, M2M communication or MTCmay include communications from devices that integrate sensors or metersto measure or capture information and relay that information to acentral server or application program that can make use of theinformation or present the information to humans interacting with theprogram or application. Some UEs 115 may be designed to collectinformation or enable automated behavior of machines. Examples ofapplications for MTC devices include smart metering, inventorymonitoring, water level monitoring, equipment monitoring, healthcaremonitoring, wildlife monitoring, weather and geological eventmonitoring, fleet management and tracking, remote security sensing,physical access control, and transaction-based business charging.

Some UEs 115 may be configured to employ operating modes that reducepower consumption, such as half-duplex communications (e.g., a mode thatsupports one-way communication via transmission or reception, but nottransmission and reception simultaneously). In some examples,half-duplex communications may be performed at a reduced peak rate.Other power conservation techniques for UEs 115 include entering a powersaving “deep sleep” mode when not engaging in active communications, oroperating over a limited bandwidth (e.g., according to narrowbandcommunications). In other cases, UEs 115 may be designed to supportcritical functions (e.g., mission critical functions), and a wirelesscommunications system 100 may be configured to provide ultra-reliablecommunications for these functions.

In certain cases, a UE 115 may also be able to communicate directly withother UEs 115 (e.g., using a peer-to-peer (P2P) or device-to-device(D2D) protocol). One or more of a group of UEs 115 utilizing D2Dcommunications may be within the geographic coverage area 110 of a basestation 105. Other UEs 115 in such a group may be outside the geographiccoverage area 110 of a base station 105, or be otherwise unable toreceive transmissions from a base station 105. In some cases, groups ofUEs 115 communicating via D2D communications may utilize a one-to-many(1:M) system in which each UE 115 transmits to every other UE 115 in thegroup. In some cases, a base station 105 may facilitate the schedulingof resources for D2D communications. In other cases, D2D communicationsmay be carried out between UEs 115 without the involvement of a basestation 105.

Base stations 105 may communicate with the core network 130 and with oneanother. For example, base stations 105 may interface with the corenetwork 130 through backhaul links 132 (e.g., via an S1, N2, N3, orother interface). Base stations 105 may communicate with one anotherover backhaul links 134 (e.g., via an X2, Xn, or other interface) eitherdirectly (e.g., directly between base stations 105) or indirectly (e.g.,via core network 130).

The core network 130 may provide user authentication, accessauthorization, tracking, Internet Protocol (IP) connectivity, and otheraccess, routing, or mobility functions. The core network 130 may be anevolved packet core (EPC), which may include at least one mobilitymanagement entity (MME), at least one serving gateway (S-GW), and atleast one packet data network (PDN) gateway (P-GW). The MME may managenon-access stratum (e.g., control plane) functions such as mobility,authentication, and bearer management for UEs 115 served by basestations 105 associated with the EPC. User IP packets may be transferredthrough the S-GW, which itself may be connected to the P-GW. The P-GWmay provide IP address allocation as well as other functions. The P-GWmay be connected to the network operators IP services. The operators IPservices may include access to the Internet, Intranet(s), an IPmultimedia subsystem (IMS), or a packet-switched (PS) streaming service.

At least some of the network devices, such as a base station 105, mayinclude subcomponents such as an access network entity, which may be anexample of an access node controller (ANC). Each access network entitymay communicate with UEs 115 through a number of other access networktransmission entities, which may be referred to as a radio head, a smartradio head, or a transmission/reception point (TRP). In someconfigurations, various functions of each access network entity or basestation 105 may be distributed across various network devices (e.g.,radio heads and access network controllers) or consolidated into asingle network device (e.g., a base station 105).

Wireless communications system 100 may operate using one or morefrequency bands, typically in the range of 300 megahertz (MHz) to 300gigahertz (GHz). Generally, the region from 300 MHz to 3 GHz is known asthe ultra-high frequency (UHF) region or decimeter band, since thewavelengths range from approximately one decimeter to one meter inlength. UHF waves may be blocked or redirected by buildings andenvironmental features. However, the waves may penetrate structuressufficiently for a macro cell to provide service to UEs 115 locatedindoors. Transmission of UHF waves may be associated with smallerantennas and shorter range (e.g., less than 100 km) compared totransmission using the smaller frequencies and longer waves of the highfrequency (HF) or very high frequency (VHF) portion of the spectrumbelow 300 MHz.

Wireless communications system 100 may also operate in a super highfrequency (SHF) region using frequency bands from 3 GHz to 30 GHz, alsoknown as the centimeter band. The SHF region includes bands such as the5 GHz industrial, scientific, and medical (ISM) bands, which may be usedopportunistically by devices that may be capable of toleratinginterference from other users.

Wireless communications system 100 may also operate in an extremely highfrequency (EHF) region of the spectrum (e.g., from 30 GHz to 300 GHz),also known as the millimeter band. In some examples, wirelesscommunications system 100 may support millimeter wave (mmW)communications between UEs 115 and base stations 105, and EHF antennasof the respective devices may be even smaller and more closely spacedthan UHF antennas. In some cases, this may facilitate use of antennaarrays within a UE 115. However, the propagation of EHF transmissionsmay be subject to even greater atmospheric attenuation and shorter rangethan SHF or UHF transmissions. Techniques disclosed herein may beemployed across transmissions that use one or more different frequencyregions, and designated use of bands across these frequency regions maydiffer by country or regulating body.

Wireless communications system 100 may include operations by differentnetwork operating entities (e.g., network operators), in which eachnetwork operator may share spectrum. In some instances, a networkoperating entity may be configured to use an entirety of a designatedshared spectrum for at least a period of time before another networkoperating entity uses the entirety of the designated shared spectrum fora different period of time. Thus, in order to allow network operatingentities use of the full designated shared spectrum, and in order tomitigate interfering communications between the different networkoperating entities, certain resources (e.g., time) may be partitionedand allocated to the different network operating entities for certaintypes of communication.

For example, a network operating entity may be allocated certain timeresources reserved for exclusive communication by the network operatingentity using the entirety of the shared spectrum. The network operatingentity may also be allocated other time resources where the entity isgiven priority over other network operating entities to communicateusing the shared spectrum. These time resources, prioritized for use bythe network operating entity, may be utilized by other network operatingentities on an opportunistic basis if the prioritized network operatingentity does not utilize the resources. Additional time resources may beallocated for any network operator to use on an opportunistic basis.

Access to the shared spectrum and the arbitration of time resourcesamong different network operating entities may be centrally controlledby a separate entity, autonomously determined by a predefinedarbitration scheme, or dynamically determined based on interactionsbetween wireless nodes of the network operators.

In various implementations, wireless communications system 100 may useboth licensed and unlicensed radio frequency spectrum bands. Forexample, wireless communications system 100 may employ license assistedaccess (LAA), LTE-unlicensed (LTE-U) radio access technology, or NRtechnology in an unlicensed band (NR-U), such as the 5 GHz ISM band. Insome cases, UE 115 and base station 105 of the wireless communicationssystem 100 may operate in a shared radio frequency spectrum band, whichmay include licensed or unlicensed (e.g., contention-based) frequencyspectrum. In an unlicensed frequency portion of the shared radiofrequency spectrum band, UEs 115 or base stations 105 may traditionallyperform a medium-sensing procedure to contend for access to thefrequency spectrum. For example, UE 115 or base station 105 may performa listen before talk (LBT) procedure such as a clear channel assessment(CCA) prior to communicating in order to determine whether the sharedchannel is available.

A CCA may include an energy detection procedure to determine whetherthere are any other active transmissions on the shared channel. Forexample, a device may infer that a change in a received signal strengthindicator (RSSI) of a power meter indicates that a channel is occupied.Specifically, signal power that is concentrated in a certain bandwidthand exceeds a predetermined noise floor may indicate another wirelesstransmitter. A CCA also may include message detection of specificsequences that indicate use of the channel. For example, another devicemay transmit a specific preamble prior to transmitting a data sequence.In some cases, an LBT procedure may include a wireless node adjustingits own backoff window based on the amount of energy detected on achannel and/or the acknowledge/negative-acknowledge (ACK/NACK) feedbackfor its own transmitted packets as a proxy for collisions.

In general, four categories of LBT procedure have been suggested forsensing a shared channel for signals that may indicate the channel isalready occupied. In a first category (CAT 1 LBT), no LBT or CCA isapplied to detect occupancy of the shared channel. A second category(CAT 2 LBT), which may also be referred to as an abbreviated LBT, asingle-shot LBT, or a 25-μs LBT, provides for the node to perform a CCAto detect energy above a predetermined threshold or detect a message orpreamble occupying the shared channel. The CAT 2 LBT performs the CCAwithout using a random back-off operation, which results in itsabbreviated length, relative to the next categories.

A third category (CAT 3 LBT) performs CCA to detect energy or messageson a shared channel, but also uses a random back-off and fixedcontention window. Therefore, when the node initiates the CAT 3 LBT, itperforms a first CCA to detect occupancy of the shared channel. If theshared channel is idle for the duration of the first CCA, the node mayproceed to transmit. However, if the first CCA detects a signaloccupying the shared channel, the node selects a random back-off basedon the fixed contention window size and performs an extended CCA. If theshared channel is detected to be idle during the extended CCA and therandom number has been decremented to 0, then the node may begintransmission on the shared channel. Otherwise, the node decrements therandom number and performs another extended CCA. The node would continueperforming extended CCA until the random number reaches 0. If the randomnumber reaches 0 without any of the extended CCAs detecting channeloccupancy, the node may then transmit on the shared channel. If at anyof the extended CCA, the node detects channel occupancy, the node mayre-select a new random back-off based on the fixed contention windowsize to begin the countdown again.

A fourth category (CAT 4 LBT), which may also be referred to as a fullLBT procedure, performs the CCA with energy or message detection using arandom back-off and variable contention window size. The sequence of CCAdetection proceeds similarly to the process of the CAT 3 LBT, exceptthat the contention window size is variable for the CAT 4 LBT procedure.

Use of a medium-sensing procedure to contend for access to an unlicensedshared spectrum may result in communication inefficiencies. This may beparticularly evident when multiple network operating entities (e.g.,network operators) are attempting to access a shared resource. Inwireless communications system 100, base stations 105 and UEs 115 may beoperated by the same or different network operating entities. In someexamples, an individual base station 105 or UE 115 may be operated bymore than one network operating entity. In other examples, each basestation 105 and UE 115 may be operated by a single network operatingentity. Requiring each base station 105 and UE 115 of different networkoperating entities to contend for shared resources may result inincreased signaling overhead and communication latency.

In some cases, operations in unlicensed bands may be based on a carrieraggregation configuration in conjunction with component carriersoperating in a licensed band (e.g., LAA). Operations in unlicensedspectrum may include downlink transmissions, uplink transmissions,peer-to-peer transmissions, or a combination of these. Duplexing inunlicensed spectrum may be based on frequency division duplexing (FDD),time division duplexing (TDD), or a combination of both.

In some examples, base station 105 or UE 115 may be equipped withmultiple antennas, which may be used to employ techniques such astransmit diversity, receive diversity, multiple-input multiple-output(MIMO) communications, or beamforming. For example, wirelesscommunications system 100 may use a transmission scheme between atransmitting device (e.g., a base station 105) and a receiving device(e.g., a UE 115), where the transmitting device is equipped withmultiple antennas and the receiving device is equipped with one or moreantennas. MIMO communications may employ multipath signal propagation toincrease the spectral efficiency by transmitting or receiving multiplesignals via different spatial layers, which may be referred to asspatial multiplexing. The multiple signals may, for example, betransmitted by the transmitting device via different antennas ordifferent combinations of antennas. Likewise, the multiple signals maybe received by the receiving device via different antennas or differentcombinations of antennas. Each of the multiple signals may be referredto as a separate spatial stream, and may carry bits associated with thesame data stream (e.g., the same codeword) or different data streams.Different spatial layers may be associated with different antenna portsused for channel measurement and reporting. MIMO techniques includesingle-user MIMO (SU-MIMO) where multiple spatial layers are transmittedto the same receiving device, and multiple-user MIMO (MU-MIMO) wheremultiple spatial layers are transmitted to multiple devices.

Beamforming, which may also be referred to as spatial filtering,directional transmission, or directional reception, is a signalprocessing technique that may be used at a transmitting device or areceiving device (e.g., a base station 105 or a UE 115) to shape orsteer an antenna beam (e.g., a transmit beam or receive beam) along aspatial path between the transmitting device and the receiving device.Beamforming may be achieved by combining the signals communicated viaantenna elements of an antenna array such that signals propagating atparticular orientations with respect to an antenna array experienceconstructive interference while others experience destructiveinterference. The adjustment of signals communicated via the antennaelements may include a transmitting device or a receiving deviceapplying certain amplitude and phase offsets to signals carried via eachof the antenna elements associated with the device. The adjustmentsassociated with each of the antenna elements may be defined by abeamforming weight set associated with a particular orientation (e.g.,with respect to the antenna array of the transmitting device orreceiving device, or with respect to some other orientation).

In one example, a base station 105 may use multiple antennas or antennaarrays to conduct beamforming operations for directional communicationswith a UE 115. For instance, some signals (e.g. synchronization signals,reference signals, beam selection signals, or other control signals) maybe transmitted by a base station 105 multiple times in differentdirections, which may include a signal being transmitted according todifferent beamforming weight sets associated with different directionsof transmission. Transmissions in different beam directions may be usedto identify (e.g., by the base station 105 or a receiving device, suchas a UE 115) a beam direction for subsequent transmission and/orreception by the base station 105.

Some signals, such as data signals associated with a particularreceiving device, may be transmitted by a base station 105 in a singlebeam direction (e.g., a direction associated with the receiving device,such as a UE 115). In some examples, the beam direction associated withtransmissions along a single beam direction may be determined based atleast in in part on a signal that was transmitted in different beamdirections. For example, a UE 115 may receive one or more of the signalstransmitted by the base station 105 in different directions, and the UE115 may report to the base station 105 an indication of the signal itreceived with a highest signal quality, or an otherwise acceptablesignal quality. Although these techniques are described with referenceto signals transmitted in one or more directions by a base station 105,a UE 115 may employ similar techniques for transmitting signals multipletimes in different directions (e.g., for identifying a beam directionfor subsequent transmission or reception by the UE 115), or transmittinga signal in a single direction (e.g., for transmitting data to areceiving device).

A receiving device (e.g., a UE 115, which may be an example of a mmWreceiving device) may try multiple receive beams when receiving varioussignals from the base station 105, such as synchronization signals,reference signals, beam selection signals, or other control signals. Forexample, a receiving device may try multiple receive directions byreceiving via different antenna subarrays, by processing receivedsignals according to different antenna subarrays, by receiving accordingto different receive beamforming weight sets applied to signals receivedat a plurality of antenna elements of an antenna array, or by processingreceived signals according to different receive beamforming weight setsapplied to signals received at a plurality of antenna elements of anantenna array, any of which may be referred to as “listening” accordingto different receive beams or receive directions. In some examples areceiving device may use a single receive beam to receive along a singlebeam direction (e.g., when receiving a data signal). The single receivebeam may be aligned in a beam direction determined based at least inpart on listening according to different receive beam directions (e.g.,a beam direction determined to have a highest signal strength, highestsignal-to-noise ratio, or otherwise acceptable signal quality based atleast in part on listening according to multiple beam directions).

In certain implementations, the antennas of a base station 105 or UE 115may be located within one or more antenna arrays, which may support MIMOoperations, or transmit or receive beamforming. For example, one or morebase station antennas or antenna arrays may be co-located at an antennaassembly, such as an antenna tower. In some cases, antennas or antennaarrays associated with a base station 105 may be located in diversegeographic locations. A base station 105 may have an antenna array witha number of rows and columns of antenna ports that the base station 105may use to support beamforming of communications with a UE 115.Likewise, a UE 115 may have one or more antenna arrays that may supportvarious MIMO or beamforming operations.

In additional cases, UEs 115 and base stations 105 may supportretransmissions of data to increase the likelihood that data is receivedsuccessfully. HARQ feedback is one technique of increasing thelikelihood that data is received correctly over a communication link125. HARQ may include a combination of error detection (e.g., using acyclic redundancy check (CRC)), forward error correction (FEC), andretransmission (e.g., automatic repeat request (ARQ)). HARQ may improvethroughput at the MAC layer in poor radio conditions (e.g.,signal-to-noise conditions). In some cases, a wireless device maysupport same-slot HARQ feedback, where the device may provide HARQfeedback in a specific slot for data received in a previous symbol inthe slot, while in other cases, the device may provide HARQ feedback ina subsequent slot, or according to some other time interval.

Time intervals in LTE or NR may be expressed in multiples of a basictime unit, which may, for example, refer to a sampling period of T_(s)=1/30,720,000 seconds. Time intervals of a communications resource may beorganized according to radio frames each having a duration of 10milliseconds (ms), where the frame period may be expressed asT_(f)=307,200 T_(s). The radio frames may be identified by a systemframe number (SFN) ranging from 0 to 1023. Each frame may include 10subframes numbered from 0 to 9, and each subframe may have a duration of1 ms. A subframe may be further divided into 2 slots each having aduration of 0.5 ms, and each slot may contain 6 or 7 modulation symbolperiods (e.g., depending on the length of the cyclic prefix prepended toeach symbol period). Excluding the cyclic prefix, each symbol period maycontain 2048 sampling periods. In some cases, a subframe may be thesmallest scheduling unit of the wireless communications system 100, andmay be referred to as a transmission time interval (TTI). In othercases, a smallest scheduling unit of the wireless communications system100 may be shorter than a subframe or may be dynamically selected (e.g.,in bursts of shortened TTIs (sTTIs) or in selected component carriersusing sTTIs).

In some wireless communications systems, a slot may further be dividedinto multiple mini-slots containing one or more symbols. In someinstances, a symbol of a mini-slot or a mini-slot may be the smallestunit of scheduling. Each symbol may vary in duration depending on thesubcarrier spacing or frequency band of operation, for example. Further,some wireless communications systems may implement slot aggregation inwhich multiple slots or mini-slots are aggregated together and used forcommunication between a UE 115 and a base station 105.

The term “carrier,” as may be used herein, refers to a set of radiofrequency spectrum resources having a defined physical layer structurefor supporting communications over a communication link 125. Forexample, a carrier of a communication link 125 may include a portion ofa radio frequency spectrum band that is operated according to physicallayer channels for a given radio access technology. Each physical layerchannel may carry user data, control information, or other signaling. Acarrier may be associated with a pre-defined frequency channel (e.g., anevolved universal mobile telecommunication system terrestrial radioaccess (E-UTRA) absolute radio frequency channel number (EARFCN)), andmay be positioned according to a channel raster for discovery by UEs115. Carriers may be downlink or uplink (e.g., in an FDD mode), or beconfigured to carry downlink and uplink communications (e.g., in a TDDmode). In some examples, signal waveforms transmitted over a carrier maybe made up of multiple sub-carriers (e.g., using multi-carriermodulation (MCM) techniques such as orthogonal frequency divisionmultiplexing (OFDM) or discrete Fourier transform spread OFDM(DFT-S-OFDM)).

The organizational structure of the carriers may be different fordifferent radio access technologies (e.g., LTE, LTE-A, LTE-A Pro, NR).For example, communications over a carrier may be organized according toTTIs or slots, each of which may include user data as well as controlinformation or signaling to support decoding the user data. A carriermay also include dedicated acquisition signaling (e.g., synchronizationsignals or system information, etc.) and control signaling thatcoordinates operation for the carrier. In some examples (e.g., in acarrier aggregation configuration), a carrier may also have acquisitionsignaling or control signaling that coordinates operations for othercarriers.

Physical channels may be multiplexed on a carrier according to varioustechniques. A physical control channel and a physical data channel maybe multiplexed on a downlink carrier, for example, using time divisionmultiplexing (TDM) techniques, frequency division multiplexing (FDM)techniques, or hybrid TDM-FDM techniques. In some examples, controlinformation transmitted in a physical control channel may be distributedbetween different control regions in a cascaded manner (e.g., between acommon control region or common search space and one or more UE-specificcontrol regions or UE-specific search spaces).

A carrier may be associated with a particular bandwidth of the radiofrequency spectrum, and in some examples the carrier bandwidth may bereferred to as a “system bandwidth” of the carrier or the wirelesscommunications system 100. For example, the carrier bandwidth may be oneof a number of predetermined bandwidths for carriers of a particularradio access technology (e.g., 1.4, 3, 5, 10, 15, 20, 40, or 80 MHz). Insome examples, each served UE 115 may be configured for operating overportions or all of the carrier bandwidth. In other examples, some UEs115 may be configured for operation using a narrowband protocol typethat is associated with a predefined portion or range (e.g., set ofsubcarriers or RBs) within a carrier (e.g., “in-band” deployment of anarrowband protocol type).

In a system employing MCM techniques, a resource element may consist ofone symbol period (e.g., a duration of one modulation symbol) and onesubcarrier, where the symbol period and subcarrier spacing are inverselyrelated. The number of bits carried by each resource element may dependon the modulation scheme (e.g., the order of the modulation scheme).Thus, the more resource elements that a UE 115 receives and the higherthe order of the modulation scheme, the higher the data rate may be forthe UE 115. In MIMO systems, a wireless communications resource mayrefer to a combination of a radio frequency spectrum resource, a timeresource, and a spatial resource (e.g., spatial layers), and the use ofmultiple spatial layers may further increase the data rate forcommunications with a UE 115.

Devices of the wireless communications system 100 (e.g., base stations105 or UEs 115) may have a hardware configuration that supportscommunications over a particular carrier bandwidth, or may beconfigurable to support communications over one of a set of carrierbandwidths. In some examples, the wireless communications system 100 mayinclude base stations 105 and/or UEs 115 that support simultaneouscommunications via carriers associated with more than one differentcarrier bandwidth.

Wireless communications system 100 may support communication with a UE115 on multiple cells or carriers, a feature which may be referred to ascarrier aggregation or multi-carrier operation. A UE 115 may beconfigured with multiple downlink component carriers and one or moreuplink component carriers according to a carrier aggregationconfiguration. Carrier aggregation may be used with both FDD and TDDcomponent carriers.

In some cases, wireless communications system 100 may utilize enhancedcomponent carriers (eCCs). An eCC may be characterized by one or morefeatures including wider carrier or frequency channel bandwidth, shortersymbol duration, shorter TTI duration, or modified control channelconfiguration. In certain instances, an eCC may be associated with acarrier aggregation configuration or a dual connectivity configuration(e.g., when multiple serving cells have a suboptimal or non-idealbackhaul link). An eCC may also be configured for use in unlicensedspectrum or shared spectrum (e.g., where more than one operator isallowed to use the spectrum, such as NR-shared spectrum (NR-SS)). An eCCcharacterized by wide carrier bandwidth may include one or more segmentsthat may be utilized by UEs 115 that are not capable of monitoring thewhole carrier bandwidth or are otherwise configured to use a limitedcarrier bandwidth (e.g., to conserve power).

In additional cases, an eCC may utilize a different symbol duration thanother component carriers, which may include use of a reduced symbolduration as compared with symbol durations of the other componentcarriers. A shorter symbol duration may be associated with increasedspacing between adjacent subcarriers. A device, such as a UE 115 or basestation 105, utilizing eCCs may transmit wideband signals (e.g.,according to frequency channel or carrier bandwidths of 20, 40, 60, 80MHz, etc.) at reduced symbol durations (e.g., 16.67 microseconds). A TTIin eCC may consist of one or multiple symbol periods. In some cases, theTTI duration (that is, the number of symbol periods in a TTI) may bevariable.

Wireless communications system 100 may be an NR system that may utilizeany combination of licensed, shared, and unlicensed spectrum bands,among others. The flexibility of eCC symbol duration and subcarrierspacing may allow for the use of eCC across multiple spectrums. In someexamples, NR shared spectrum may increase spectrum utilization andspectral efficiency, specifically through dynamic vertical (e.g., acrossthe frequency domain) and horizontal (e.g., across the time domain)sharing of resources.

FIG. 2 shows a block diagram of a design of a base station 105 and a UE115, which may be one of the base station and one of the UEs in FIG. 1.At base station 105, a transmit processor 220 may receive data from adata source 212 and control information from a controller/processor 240.The control information may be for the PBCH, PCFICH, PHICH, PDCCH,EPDCCH, MPDCCH etc. The data may be for the PDSCH, etc. The transmitprocessor 220 may process (e.g., encode and symbol map) the data andcontrol information to obtain data symbols and control symbols,respectively. The transmit processor 220 may also generate referencesymbols, e.g., for the PSS, SSS, and cell-specific reference signal. Atransmit (TX) multiple-input multiple-output (MIMO) processor 230 mayperform spatial processing (e.g., precoding) on the data symbols, thecontrol symbols, and/or the reference symbols, if applicable, and mayprovide output symbol streams to the modulators (MODs) 232 a through 232t. Each modulator 232 may process a respective output symbol stream(e.g., for OFDM, etc.) to obtain an output sample stream. Each modulator232 may further process (e.g., convert to analog, amplify, filter, andupconvert) the output sample stream to obtain a downlink signal.Downlink signals from modulators 232 a through 232 t may be transmittedvia the antennas 234 a through 234 t, respectively.

At UE 115, the antennas 252 a through 252 r may receive the downlinksignals from the base station 105 and may provide received signals tothe demodulators (DEMODs) 254 a through 254 r, respectively. Eachdemodulator 254 may condition (e.g., filter, amplify, downconvert, anddigitize) a respective received signal to obtain input samples. Eachdemodulator 254 may further process the input samples (e.g., for OFDM,etc.) to obtain received symbols. A MIMO detector 256 may obtainreceived symbols from all the demodulators 254 a through 254 r, performMIMO detection on the received symbols if applicable, and providedetected symbols. A receive processor 258 may process (e.g., demodulate,deinterleave, and decode) the detected symbols, provide decoded data forthe UE 115 to a data sink 260, and provide decoded control informationto a controller/processor 280.

On the uplink, at the UE 115, a transmit processor 264 may receive andprocess data (e.g., for the PUSCH) from a data source 262 and controlinformation (e.g., for the PUCCH) from the controller/processor 280. Thetransmit processor 264 may also generate reference symbols for areference signal. The symbols from the transmit processor 264 may beprecoded by a TX MIMO processor 266 if applicable, further processed bythe modulators 254 a through 254 r (e.g., for SC-FDM, etc.), andtransmitted to the base station 105. At the base station 105, the uplinksignals from the UE 115 may be received by the antennas 234, processedby the demodulators 232, detected by a MIMO detector 236 if applicable,and further processed by a receive processor 238 to obtain decoded dataand control information sent by the UE 115. The processor 238 mayprovide the decoded data to a data sink 239 and the decoded controlinformation to the controller/processor 240.

The controllers/processors 240 and 280 may direct the operation at thebase station 105 and the UE 115, respectively. The controller/processor240 and/or other processors and modules at the base station 105 mayperform or direct the execution of various processes for the techniquesdescribed herein. The controllers/processor 280 and/or other processorsand modules at the UE 115 may also perform or direct the execution ofthe functional blocks illustrated in FIGS. 7 and 8, and/or otherprocesses for the techniques described herein. The memories 242 and 282may store data and program codes for the base station 105 and the UE115, respectively. A scheduler 244 may schedule UEs for datatransmission on the downlink and/or uplink.

As wireless technologies advance, mobile network operator (MNO)-drivenwide-area networks will continue servicing traditional use cases. 5Gtechnology is expected to expand beyond traditional use cases to newapplications in healthcare, industrial internet-of-things (IIOT), etc.Certain non-traditional use case scenarios may benefit from solutions tocurrent issues in order to meet the stringent need of ultra-reliable,low latency communication (URLLC) services. In a mission critical (MiCr)application, URLLC operations may expect a 10⁻⁶ packet error rate, mslatency, all in multi-year 24 hour, 7 days per week (24/7) operation.Extending into NR features, 5G NR-U will have support for both licenseassisted access (LAA), in which unlicensed channels are assisted bylicensed channels for guaranteed communications, and standalone mode.

Spectrum availability continues to be at the forefront of discussionsfor increasing wireless service access. One target for NR-U deploymentshas been suggested for the 5 GHz band and the upcoming 6 GHz band.However, the existing medium access procedure in the unlicensed 5 GHzband can create a number of issues that may result in poor performance,thus, making unlicensed spectrum difficult for such new high priorityapplications. The 5 GHz band, which may be shared with other radioaccess technologies, such as WiFi, may suffer interference caused byhidden and exposed nodes, loose quality of service (QoS) control, andinadequate support for new advanced transmission techniques, such asCoMP, etc. In fact, any frequency band accessible for NR-U operationsmay include various radio access technologies competing forcommunications access.

In responding to demands for more “mid-band” unlicensed spectrum tosupplement the unlicensed spectrum already available in the 5 GHz band,consideration has been made by governmental authorities to open the 6GHz band (e.g., 5.925-7.125 GHz) for unlicensed use. The 6 GHz band iscurrently used by licensed incumbents, such as fixed, mobile, andsatellite services. In order to open the 6 GHz band, sophisticatedsharing mechanisms will be used to protect these licensed incumbents.Because the 6 GHz band has not been open to unlicensed use, it does nothave “legacy” secondary users or radio access technologies alsocompeting for communications access. As such, it may offer opportunitiesto develop new procedures that may support these new use-cases in anunlicensed spectrum. Various aspects of the present disclosure aredirected to providing enhanced mechanisms for handling technologyneutral medium access that may allow for advanced uses of unlicensedspectrum.

As may be readily understood, multiple nodes may be situated in such amanner that provides the coverage areas of each node to substantiallyoverlap with the coverage area of the other nodes. Some of the nodes mayhave portions of their respective coverage area that are not overlappedby the other nodes. However, the coverage area of certain of these nodesmay be completely overlapped by either or all of the coverage areas ofthe other nodes. In providing communications with UEs connected to thesenodes, the medium access procedure for each node would include acontention window, in which each node contends for the sharedcommunication channel. However, while scenarios exist where the nodesthat have some non-overlapped coverage area may have a successfulcontention procedure to secure channel occupancy times (COTs) forcommunications, because none of the contention windows for each of thenodes overlaps, the node with all of its coverage area overlapped maynot have an opportunity to access the medium as long as the other nodesare not within the sensing range of each other and are using the medium.

The concept of time synchronization has increasingly discussed as asolution for wireless communication for licensed and unlicensed accessto shared spectrum. Synchronized access may be beneficial in variousoperations, such as between adjacent nodes of the same network in a timedivision duplex (TDD) spectrum, adjacent coordinated multipoint (CoMP)nodes in the same network in either frequency division duplex (FDD) orTDD spectrum, and even nodes of different networks that may share thesame spectrum, such as in the citizens broadband radio system (CBRS)band. Time synchronization operations may further be beneficial for usein unlicensed spectrum. The results of the time synchronization operatesto improve service predictability and, thus, overall user experience andenables technologies, such as CoMP, to improve spectrum efficiency andreliability. Additionally, it may facilitate flexible sharing and enablemore advanced sharing techniques, such as spatial domain multiplexing toimprove spectrum utilization.

FIG. 3 is a block diagram illustrating a portion of NR-U network 30having overlapping nodes, nodes 1-3, competing for access to sharedcommunication spectrum. As illustrated, three wireless nodes, nodes 1-3,have been situated such that the coverage areas of each nodesubstantially overlaps with the coverage area of the other nodes. Nodes1 and 3 may have portions of their coverage areas that are notoverlapped by the other nodes, respectively. However, the coverage areaof node 2 is completely overlapped by either the coverage area of node 1or node 3.

FIG. 3 further shows the illustrative timelines for each of nodes 1-3.In providing communications with UEs 115 a-c, the medium accessprocedure for each node includes contention windows in which each nodemay contend for the shared communication channel. However, withoutability to implement synchronous communication modes, while scenariosexist where node 1 and 3 may have a successful contention procedure tosecure channel occupancy times (COTs) for communications, because noneof the contention windows for each of nodes 1-3 overlaps, node 2 willnot have an opportunity to access the medium as long as nodes 1 and 3are not within the sensing range of each other and are using the medium.At each of contention windows 300-308 for node 2, ongoing transmissionsby either node 1 or node 3 blocks node 2 from accessing the sharedcommunication spectrum by causing each LBT procedure of node 2 to fail.If nodes 1 and 3 have considerable traffic, their respectivetransmissions may block node 2 for a long period of time, resulting in apoor user experience for users attempting access via node 2.

With current medium access rules, existing LBT schemes may suffer fromstarvation (e.g., failure to secure channel access), as illustrated inFIG. 3, due to interference experienced from exposed or hidden nodes.The medium access procedure is further not well defined for CoMPoperations. Trigger-based schemes used for uplink multi-user multipleinput, multiple output (MU-MIMO) operations may not be considered “fair”due to the potentially higher transmit power of the access pointscompared to its clients. Additionally, there is no current or practicaltechnology neutral way to protect the receiver. When defined in WiFioperations, receiver protection techniques have not perform well inheavily loaded scenarios when WiFi preambles are not detected due to lowsignal-to-interference plus noise ratio (SINR).

As noted above, synchronous access schemes have been suggested for suchunlicensed media to improve handling of these access issues.Synchronization can improve fairness since it enables overlappingcontention windows. Each node would theoretically get fair share of themedium. In addition, it may help mitigate hidden node interferenceissues, since, at a given time, all nodes would monitor controlsignaling. Moreover, receiver protection, analogous to clear-to-send(CTS) message is possible to achieve in a technology neutral way.

FIG. 4 is a block diagram illustrating a portion of NR-U network 40configured to support synchronous communication mode within a sharedcommunication spectrum. As illustrated, three wireless nodes, nodes 1-3,have been situated such that the coverage areas of each nodesubstantially overlaps with the coverage area of the other nodes—similarto the configuration illustrated in FIG. 3. Nodes 1 and 3 may haveportions of their coverage areas that are not overlapped by the othernodes, respectively, while the coverage area of node 2 is completelyoverlapped by either the coverage area of node 1 or node 3. FIG. 4 alsoshows the illustrative timelines for each of nodes 1-3. However, unlikethe portion of NR-U network 30 illustrated in FIG. 3, the portion ofNR-U network 40 illustrated in FIG. 4 includes the capabilities of nodes1-3 to use a synchronous access mode for accessing the sharedcommunication spectrum.

In providing communications with UEs 115 a-c, the medium accessprocedure for each node includes synchronized, overlapping contentionwindows in which each node may contend for the shared communicationchannel. The synchronized contention windows may allow each of nodes 1-3to contend for access with a minimum of latency. Further, no node isblocked from accessing the medium for an extended period of time, whichresults in an improved user experience.

While the synchronous access mode illustrated in FIG. 4 provides fairand efficient access for multiple overlapping nodes, nodes 1-3, it maybe impractical to require all radio access technologies contending forthe shared communication spectrum to operate using such timesynchronization. Implementing synchronous access mode technologyincreases signaling overhead through the exchange of the variousparameters that may define the synchronous access mode, such aslocations of synchronization boundaries, synchronization intervals, asynchronized clock, and the like. Thus, it may not be desirable for allradio access technologies to commit to such synchronous operations. Amore practical approach has been discussed to allow for both synchronousand asynchronous access modes for the various radio access technologiesto use for accessing share communication spectrum. However, in order tofacilitate coexistence of both access modes, some form of cooperationshould exist between nodes accessing via asynchronous modes and nodesaccessing via synchronous modes.

FIG. 5 is a block diagram illustrating a portion of NR-U network 50configured to support access to a shared communication spectrum usingeither or both asynchronous modes and synchronous modes. As illustrated,the three wireless nodes, nodes 1-3, are situated such that the coverageareas of each node substantially overlaps with the coverage area of theother nodes—similar to the configuration illustrated in FIGS. 3-4. Nodes1 and 3 have portions of their coverage areas that are not overlapped bythe other nodes, respectively, while the coverage area of node 2 iscompletely overlapped by either the coverage area of node 1 or node 3.As with FIGS. 3 and 4, FIG. 5 also shows the illustrative timelines foreach of nodes 1-3. However, node 1 is indicated to be using asynchronous access mode, while nodes 2 and 3 are using an asynchronousaccess mode.

In order to increase the efficiency and fairness for access by all ofnodes 1-3, the asynchronous nodes may elect to shorten their respectiveCOT to end at the next one of synchronization boundaries 500-505. Eachof synchronization boundaries 500-505 occur at synchronization interval506. When operating within a mixed access network, COT for synchronousaccess nodes would follow the synchronization interval, which may belimited up to a first max duration (e.g., ≤6 ms, ≤8 ms, ≤10 ms, etc.),while COT for asynchronous access nodes may limited up to a second maxduration that may generally be greater than the first duration for thesynchronous access nodes (e.g., ≤10 ms, ≤12 ms, ≤14 ms, etc.). Thus, inorder to cooperate with node 1 (the synchronous node), nodes 2 and 3(the asynchronous nodes) voluntarily reduce the maximum duration oftheir COTs to end at the next one of synchronization boundaries 500-505.For example, after node 1 (sync) performs transmission 510 on the sharedcommunication channel, node 2 (async) secures access to and performstransmission 511 by shortening 507 its COT to end at synchronizationboundary 502. Similarly, after node 1 (sync) performs transmission 512,node 3 (async) secures access to and performs transmission 513 byshortening 508 its COT to end at synchronization boundary 504. Node 1(sync) may then secure synchronous access to the shared communicationchannel at synchronization boundary 504 to perform transmission 514.

As may be observed by the cooperative effort of asynchronous nodes 2 and3, by shortening (507 and 508) their COTs to end at synchronizationboundaries 502 and 504, respectively, the resulting access for each ofnodes 1-3 becomes more like synchronous access, even by the asynchronousnodes (nodes 2 and 3).

The resulting synchronous operations of synchronous node 1 andasynchronous nodes 2 and 3 illustrated in FIG. 5 may occur when bothnodes 2 and 3 have sufficient data to transmit to the associatedsynchronization boundary and both nodes are configure to cooperate. Thismay not always be the case. When either or both of nodes 2 and 3 do nothave enough data to transmit to the synchronization boundary or do notactively cooperate with synchronous node 1, use of the available sharedcommunication spectrum may be wasted unless the synchronous node, node1, is allowed to also begin access to the spectrum after a givensynchronization boundary. Additionally, in order to encourage nodes withsynchronous capabilities to operate using a synchronous access mode, ithas been suggested to allow a COT extension of up to two times thesynchronization interval (e.g., ≤12 ms, ≤16 ms, ≤20 ms, etc.). Thus,when a synchronous node, such as node 1 attempts access after a givensynchronization boundary, it may extend its COT beyond the nextsynchronization boundary to the synchronization boundary after that.

FIG. 6 is a block diagram illustrating a portion of NR-U network 60configured to support access to a shared communication spectrum usingeither or both asynchronous modes and synchronous modes. As illustrated,the three wireless nodes, nodes 1-3, are situated such that the coverageareas of each node substantially overlaps with the coverage area of theother nodes—similar to the configuration illustrated in FIGS. 3-5. Nodes1 and 3 have portions of their coverage areas that are not overlapped bythe other nodes, respectively, while the coverage area of node 2 iscompletely overlapped by either the coverage area of node 1 or node 3.As with FIGS. 3-5, FIG. 6 also shows the illustrative timelines for eachof nodes 1-3, in which node 1 is indicated to be using a synchronousaccess mode, while nodes 2 and 3 are using an asynchronous access mode.

Where, as illustrated in FIG. 6, the asynchronous nodes, nodes 2 and 3,opt not to cooperate and do not adjust their respective COTs to end atthe next one of synchronization boundaries 600-605 after the most recentmedium busy-to-idle transition, the synchronous nodes, node 1, mayextend its COT beyond the next synchronization boundary (up to two timesthe synchronization interval). For example, node 3 (async) secures theshared communication channel at synchronization boundary 600 andperforms transmission 610, which ends just after synchronizationboundary 601. Node 1 (sync) then secures the shared communicationchannel just after synchronization boundary 601 and is able to extend606 its COT for transmissions 611 beyond synchronization boundary 602all the way to synchronization boundary 603, which is almost two timesthe synchronization interval. Similarly, after node 2 secures access tothe shared communication channel at synchronization boundary 603 andends transmission 612 well short of synchronization boundary 604, node 1(sync) is, again, after security access to the shared communicationchannel, able to extend 607 the COT of transmission 613 beyondsynchronization boundary 604 to synchronization boundary 605. Thus, byelecting to participate in the synchronous access mode, the synchronousnode, node 1, may have the benefits of the extended COT. The average COTof the two access types (sync vs. async) would still be comparable to amaximum COT for asynchronous access of 10 ms, 12 ms, 14 ms, etc.However, without the availability of a COT extension provision forsynchronous mode access, the asynchronous nodes (nodes 2 and 3) wouldhave significant advantage in terms of medium use, which would result indiscouraging synchronous mode access.

In implementing synchronous access technologies for coexistence withpurely asynchronous access technologies, two types of synchronous accessmode have been suggested. A first synchronous access mode is defined atthe network level. The set of synchronous access mode parameters, suchas synchronization boundaries or boundary reference points,synchronization interval, and synchronous master clock are defined bythe network and communicated to nodes via broadcasted systeminformation. Such network-defined synchronous access mode may bereferred to as a global synchronous mode or global synchronous accessmode.

A second synchronous access mode provides synchronous access technologyon an ad hoc basis, defined locally by an initiating node or primarynode of a cluster of nodes. Any neighboring network node may elect toparticipate in such ad hoc or local synchronous access mode throughdirect signaling to either the initiating node or the primary node ofthe cluster. Alternatively, the initiating node may begin using thesecond synchronous access mode by itself and inform other nodes of theset of local synchronization parameters as requested or as broadcastlocally among the neighboring nodes. The set of local synchronous accessmode parameters, including local synchronization boundaries or boundaryreference points, synchronization interval, and local synchronous masterclock, are defined by the initiating node or primary node of the clusterinstituting the local synchronous access mode. This second synchronousaccess mode may be referred to as a local synchronous mode or localsynchronous access mode.

FIG. 7 is a block diagram illustrating example blocks executed toimplement one aspect of the present disclosure. The example blocks willalso be described with respect to base station 105 as illustrated inFIGS. 2 and 10. FIG. 10 is a block diagram illustrating base station 105configured according to one aspect of the present disclosure. Basestation 105 includes the structure, hardware, and components asillustrated for base station 105 of FIG. 2. For example, base station105 includes controller/processor 240, which operates to execute logicor computer instructions stored in memory 242, as well as controllingthe components of base station 105 that provide the features andfunctionality of base station 105. Base station 105, under control ofcontroller/processor 240, transmits and receives signals via wirelessradios 1000 a-t and antennas 234 a-t. Wireless radios 1000 a-t includesvarious components and hardware, as illustrated in FIG. 2 for basestation 105, including modulator/demodulators 232 a-t, MIMO detector236, receive processor 238, transmit processor 220, and TX MIMOprocessor 230.

The example blocks will also be described with respect to UE 115 asillustrated in FIGS. 2 and 11. FIG. 11 is a block diagram illustratingUE 115 configured according to one aspect of the present disclosure. UE115 includes the structure, hardware, and components as illustrated forUE 115 of FIG. 2. For example, UE 115 includes controller/processor 280,which operates to execute logic or computer instructions stored inmemory 282, as well as controlling the components of UE 115 that providethe features and functionality of UE 115. UE 115, under control ofcontroller/processor 280, transmits and receives signals via wirelessradios 1100 a-r and antennas 252 a-r. Wireless radios 1100 a-r includesvarious components and hardware, as illustrated in FIG. 2 for UE 115,including modulator/demodulators 254 a-r, MIMO detector 256, receiveprocessor 258, transmit processor 264, and TX MIMO processor 266.

At block 700, a first node selects to access a shared communicationchannel according to a local synchronous access mode. When a basestation, such as base station 105, operates as a node, it may execute,under control of controller/processor 240, local synchronous mode logic1001, stored in memory 242. When controller/processor 240 executes theinstructions of local synchronous mode logic 1001, the instructions andsteps manifest in control of the components and hardware of base station105 (referred to herein as the “execution environment”) in such a mannerto produce the features and functionality of local synchronous modeoperations. With the advantages present in operating synchronous accesson a local level, base station 105 elects to execute local synchronousmode logic 1001 to initiate local synchronous mode access of the sharedcommunication spectrum.

When a UE, such as UE 115, operates as a node, it may execute, undercontrol of controller/processor 280, local synchronous mode logic 1101,stored in memory 282. When controller/processor 280 executes theinstructions of local synchronous mode logic 1101, the executionenvironment of local synchronous mode logic 1101 provides UE 115 thefeatures and functionality of local synchronous mode operations. Withthe advantages present in operating synchronous access on a local level,UE 115 elects to execute local synchronous mode logic 1101 to initiatelocal synchronous mode access of the shared communication spectrum.

At block 701, the first node performs an LBT procedure on the sharedcommunication channel using a local synchronous energy detectionthreshold, wherein the local synchronous energy detection level isrelaxed relative to a standard energy detection level used for access tothe shared communication channel. Within the execution environment oflocal synchronous access mode logic 1001, to access the sharedcommunication spectrum, base station 105 performs an LBT procedure onthe shared spectrum. Using local synchronous parameters, stored at localsync parameters 1002, in memory 242, base station 105 identifies eithera synchronous contention window at a local synchronization boundary or abusy-to-idle period where asynchronous access may be attempted. Basestation 105, under control of controller/processor 240, executes LBTlogic 1003, stored in memory 242. The execution environment of LBT logic1003 provides the functionality of LBT procedures to base station 105.Within the execution environment of local synchronous access mode logic1001 and LBT logic 1003, base station 105 uses the local synchronousenergy detection (ED) threshold stored at ED thresholds 1004, in memory242. The local synchronous ED threshold is relaxed relative to thestandard ED threshold identified in wireless standards and known tocontending nodes for access to the unlicensed spectrum. The standard EDthreshold would otherwise be used by asynchronous access nodes andglobal synchronous access nodes to access the shared communicationspectrum. By using the local synchronous ED threshold during an LBTprocedure on the shared communication spectrum by base station 105 willhave a higher probability to gain access to the spectrum than if it usedthe standard ED threshold.

When the node operates as a UE, such as UE 115, within the executionenvironment of local synchronous access mode logic 1101, to access theshared communication spectrum, UE 115 performs an LBT procedure on theshared spectrum. Using local synchronous parameters, stored at localsync parameters 1102, in memory 282, UE 115 identifies either asynchronous contention window at a local synchronization boundary or abusy-to-idle period where asynchronous access may be attempted. UE 115,under control of controller/processor 280, executes LBT logic 1103,stored in memory 282. The execution environment of LBT logic 1103provides the functionality of LBT procedures to UE 115. Within theexecution environment of local synchronous access mode logic 1101 andLBT logic 1103, UE 115 uses the local synchronous ED threshold stored atED thresholds 1104, in memory 282. The local synchronous ED threshold isrelaxed relative to the standard ED threshold, such that UE 115, byusing the local synchronous ED threshold during an LBT procedure on theshared communication spectrum will have a higher probability to gainaccess to the spectrum than if it used the standard ED threshold.

At block 702, the first node establishes, in response to success of theLBT procedure, a COT configured by the first node to end at a nextsynchronization boundary determined according to a local synchronousaccess clock. Within the execution environment of LBT logic 1003, basestation 105 may detect a successful LBT procedure if the signal energydetected on the shared communication spectrum does not exceed the localsynchronous ED threshold. In response to the successful LBT procedure,base station 105, within the execution environment of local synchronousmode logic 1001, establishes a COT for transmission over a durationending at the next local synchronization boundary, as determinedaccording to a local synchronous access clock. The synchronizationboundaries or reference points for determining the synchronizationboundaries, along with the synchronization interval and reference to thelocal synchronous access clock are stored in local synchronousparameters 1002. Such parameters may be generated by base station 105,when base station 105 is initiating the local synchronous accessprocedure or mode, or may be received from neighboring base stations orthe primary node of a cluster of nodes that have established the localsynchronous access mode configuration.

When the node operates as a UE, such as UE 115, within the executionenvironment of LBT logic 1103, UE 115 may detect a successful LBTprocedure if the signal energy detected on the shared communicationspectrum does not exceed the local synchronous ED threshold. In responseto the successful LBT procedure, UE 115, within the executionenvironment of local synchronous mode logic 1101, establishes a COT fortransmission over a duration ending at the next local synchronizationboundary, as determined according to a local synchronous access clock.The synchronization boundaries or reference points for determining thesynchronization boundaries, along with the synchronization interval andreference to the local synchronous access clock are stored in localsynchronous parameters 1102. Such parameters may be generated by UE 115,when UE 115 is initiating the local synchronous access procedure ormode, or may be received from neighboring nodes or the primary node of acluster of nodes that have established the local synchronous access modeconfiguration.

At block 703, the first node transmit data on the shared communicationchannel within the COT up to the end at the next synchronizationboundary. Once the COT is established, base station 105 may transmitdata on the shared communication spectrum until the end of the COT atthe next local synchronization boundary. The data is transmitted viawireless radios 1000 a-t and antennas 234 a-t.

When the node operates as a UE, such as UE 115, once the COT isestablished, UE 115 may transmit data on the shared communicationspectrum until the end of the COT at the next local synchronizationboundary. The data is transmitted via wireless radios 1100 a-r andantennas 252 a-r.

In general, nodes operating under the global synchronous access mode mayhave priority over nodes either operating in the local synchronousaccess mode or in asynchronous access mode. From the regulationsperspective, a local synchronous access mode is considered asynchronousaccess, since the regulations provide for either global synchronousaccess or asynchronous access to the shared communication network. Whilethe relaxed ED threshold provides an incentive and benefit fornon-global synchronous access mode nodes to select to attempt accessusing the local synchronous access mode instead the asynchronous mode,because of its priority, facility may be included to ensure that theincentive and benefit shown to local synchronous access mode nodes viathe relaxed ED threshold does not interfere with global synchronousaccess. To that end, when nodes operating under the global synchronousaccess mode operate within an area with nodes operating under the localsynchronous access mode using the relaxed ED threshold, the globalsynchronous access nodes may also be allowed to use the relaxed EDthreshold.

FIG. 8 is a block diagram illustrating example blocks executed toimplement one aspect of the present disclosure. The example blocks willalso be described with respect to base station 105, as illustrated inFIGS. 2 and 10, when a base station is operating as the node, and withrespect to UE 115, as illustrated in FIGS. 2 and 11, when a UE isoperating as the node.

At block 800, a first node, configured in a global synchronous accessmode, determines that one or more neighboring nodes operate in a localsynchronous access mode for access to a shared communication channel.When a base station, such as base station 105, operates as the node, itmay have received global synchronization parameters, stored at globalsynchronous parameters 1006, in memory 242, to use within the executionenvironment of global synchronous access mode logic 1005, executed bybase station 105, under control of controller/processor 240. Basestation 105 may receive signal via antennas 234 a-t and antennas 1000a-t which indicate that neighboring nodes in the area have initiated alocal synchronous access mode.

When a UE, such as UE 115, operates as a node, it may have receivedglobal synchronization parameters, stored at global synchronousparameters 1106, in memory 282, to use within the execution environmentof global synchronous access mode logic 1105, executed by UE 115, undercontrol of controller/processor 280. UE 115 may receive signal viaantennas 252 a-r and antennas 1100 a-r which indicate that neighboringnodes in the area have initiated a local synchronous access mode.

At block 801, the first node performs an LBT procedure on the sharedcommunication channel using a local synchronous energy detectionthreshold, wherein the local synchronous energy detection level isrelaxed relative to a standard energy detection level used for non-localsynchronous access to the shared communication channel. Within theexecution environment of global synchronous access mode logic 1005, toaccess the shared communication spectrum, base station 105 performs anLBT procedure on the shared spectrum. Using global synchronousparameters, stored at global synchronous parameters 1006, in memory 242,base station 105 identifies either a synchronous contention window at alocal synchronization boundary or a busy-to-idle period whereasynchronous access may be attempted. Base station 105, under control ofcontroller/processor 240, executes LBT logic 1003, stored in memory 242.The execution environment of LBT logic 1003 provides the functionalityof LBT procedures to base station 105. Within the execution environmentof global synchronous access mode logic 1001 and LBT logic 1003, basestation 105 knows that it can use the local synchronous ED thresholdstored at ED thresholds 1004, in memory 242, when local synchronousaccess operations are occurring for access to the shared communicationspectrum. As noted above, the local synchronous ED threshold is relaxedrelative to the standard ED threshold, which may generally be used byasynchronous access nodes and global synchronous access nodes, such thatbase station 105, by using the local synchronous ED threshold during anLBT procedure on the shared communication spectrum will have a higherprobability to gain access to the spectrum than if it used the standardED threshold.

When the node operates as a UE, such as UE 115, within the executionenvironment of global synchronous access mode logic 1105, to access theshared communication spectrum, UE 115 performs an LBT procedure on theshared spectrum. Using global synchronous parameters, stored at globalsynchronous parameters 1106, in memory 282, UE 115 identifies either asynchronous contention window at a local synchronization boundary or abusy-to-idle period where asynchronous access may be attempted. UE 115,under control of controller/processor 280, executes LBT logic 1103,stored in memory 282. The execution environment of LBT logic 1103provides the functionality of LBT procedures to UE 115. Within theexecution environment of global synchronous access mode logic 1101 andLBT logic 1103, UE 115 knows that it can use the local synchronous EDthreshold stored at ED thresholds 1104, in memory 282, when localsynchronous access operations are occurring for access to the sharedcommunication spectrum. As noted above, the local synchronous EDthreshold is relaxed relative to the standard ED threshold, such that UE115, by using the local synchronous ED threshold during an LBT procedureon the shared communication spectrum will have a higher probability togain access to the spectrum than if it used the standard ED threshold.

At block 802, the first node establishes, in response to success of theLBT procedure, a COT configured by the first node to end at a next localsynchronization boundary determined according to a local synchronousaccess clock. Within the execution environment of LBT logic 1003, basestation 105 may detect a successful LBT procedure if the signal energydetected on the shared communication spectrum does not exceed the localsynchronous ED threshold. In response to the successful LBT procedure,base station 105, within the execution environment of global synchronousaccess mode logic 1005, establishes a COT for transmission over aduration ending at the next local synchronization boundary. Theexecution environment of global synchronous access mode logic 1005includes functionality that determines that the use of the localsynchronous ED threshold requires that the COT should end at the nextlocal synchronization boundary, as determined according to a localsynchronous access clock, which base station 105 may have reference toin the signals received regarding the local synchronous access mode andstored at local synchronous parameters 1002.

When the node operates as a UE, such as UE 115, within the executionenvironment of LBT logic 1103, UE 115 may detect a successful LBTprocedure if the signal energy detected on the shared communicationspectrum does not exceed the local synchronous ED threshold. In responseto the successful LBT procedure, UE 115, within the executionenvironment of global synchronous access mode logic 1105, establishes aCOT for transmission over a duration ending at the next localsynchronization boundary. The execution environment of globalsynchronous access mode logic 1105 includes functionality thatdetermines that the use of the local synchronous ED threshold requiresthat the COT should end at the next local synchronization boundary, asdetermined according to a local synchronous access clock, which UE 115may have reference to in the signals received regarding the localsynchronous access mode and stored at local synchronous parameters 1102.

At block 803, the first node transmits data on the shared communicationchannel within the COT up to the end at the next synchronizationboundary. Once the COT is established, base station 105 may transmitdata on the shared communication spectrum until the end of the COT atthe next local synchronization boundary. The data is transmitted viawireless radios 1000 a-t and antennas 234 a-t.

When the node operates as a UE, such as UE 115, once the COT isestablished, UE 115 may transmit data on the shared communicationspectrum until the end of the COT at the next local synchronizationboundary. The data is transmitted via wireless radios 1100 a-r andantennas 252 a-r.

When determining the access rules for unlicensed spectrum between globalaccess nodes and asynchronous nodes, certain details may be included,such as specifying a maximum COT, specifying a particular contentionprocedure, specifying the ED threshold. One of the goals is to ensureaccess fairness between purely asynchronous access nodes and the globalsynchronous access nodes, while ultimately providing global synchronousaccess nodes priority access to the shared communication spectrum.Additionally, according to aspects of the present disclosure, it mayalso be beneficial to accommodate local synchronous access nodes as wellwhile ensuring that any accommodation made for the local synchronousaccess nodes does not interfere with the higher-priority globalsynchronous access nodes.

FIG. 9 is a block diagram of a portion of NR-U network 90, having alocal synchronous access node, node 1 and a global synchronous accessnode, node 3, configured according to aspects of the present disclosure.The conceptualized block diagram of FIG. 9 presents the accessprocedures for each of node 1 (local synchronous access node), node 2(asynchronous access node), and node 3 (global synchronous access node).Each of nodes 1-3 are neighboring 900 with some or all parts of theirrespective coverage areas (not shown) overlapped by some or all of theparts of the other nodes' coverage areas. As illustrated, each of nodes1-3 attempt access to shared communication spectrum using contentionprocedure 901. Contention procedure 901 configured for NR-U network 90provides for each of nodes 1-3 to perform an LBT procedure at 902. TheLBT procedure includes ED process 903 of the shared communicationspectrum, as access to such spectrum is contended by different radioaccess technologies.

According to the various aspects of the present disclosure, two EDthresholds are available to nodes 1-3 depending on the access mode eachnode attempts access to the shared communication network. Node 1, as alocal synchronous access node, uses a local synchronous ED threshold toperform ED process 903. Node 2, as an asynchronous access node, uses thestandard ED threshold, while node 3, as a global synchronous accessnode, may also use the local synchronous ED threshold. According to thevarious aspects, the local synchronous ED threshold is relaxed relativeto the standard ED threshold, as noted in greater detail above. Forexample, the local synchronous ED threshold may comprise a value, suchas −60 dBm, −62 dBm, −65 dBm, and the like, while the standard EDthreshold may be defined as a more constrained value, such as −72 dBm,−75 dBm, −80 dBm, and the like. Various different values may be selectedor configured for the local synchronous ED threshold and the standard EDthreshold, such that the value of the local synchronous ED thresholdwould result in a higher probability of channel access than the value ofthe standard ED threshold. In such a relationship, local synchronousaccess nodes and global synchronous access nodes would enjoy a higherprobability of channel access than asynchronous access nodes.

For example, as illustrated in FIG. 9, the shared communication spectrummeasures a signal energy that may be detected by each of nodes 1-3.However, identifying that signal energy as exceeding the ED thresholdand, thus, concluding that the channel is occupied will depend on thevalue of the ED threshold. As illustrated, the signal energy, asobserved by the local and global synchronous nodes, nodes 1 and 3, usingthe local synchronous ED threshold, does not exceed the ED threshold,and, therefore, nodes 1 and 3 determine an LBT pass 904 which enablesnodes 1 and 3 to establish transmissions over a COT 905 that ends atlocal synchronization boundary 906. However, the signal energy, asobserved by the asynchronous node, node 2, using the standard EDthreshold, does exceed the ED threshold, and thus, node 2 determines anLBT fail 904 without securing access to the shared communicationspectrum.

It should be noted that, global synchronous access nodes, such as node3, are allowed to use the local synchronous ED threshold if the COTestablished is not extended. Thus, the COT established by node 3 wouldnot be extended in ending at local synchronization boundary 906.

Local synchronous access could be the desired mode of operation, as itcan provide improved quality of service (QoS) within a particulardeployment cluster. As indicated above, local synchronous access isactually considered an asynchronous mode from the regulationperspective, but can provide benefits of synchronization over a localarea. Individual nodes may be configured with specific mechanisms,features, and functionalities to enable such local synchronous accesswithout the need to define the actual procedures within the standardsregulations. The use of the relaxed ED threshold for local synchronousaccess nodes may motivate compatible nodes to select local synchronousaccess over purely asynchronous access modes due to the effectiveness ofadditional back off mechanism that may be defined with technology of thenodes.

It should be noted that the local synchronous access nodes may beallowed to use the relaxed, local synchronous ED threshold to access theshared communication spectrum asynchronously if such nodes end theestablished COT at the local synchronization boundary. Thus, contentionprocedure 901 may occur at a local synchronous contention window (CW)located at a current local synchronization boundary or it may occur whena medium busy-to-idle transition is detected after the current localsynchronization boundary. If such contention procedure 901 is initiatedasynchronously, such as after the current local synchronizationboundary, any COT established by the synchronous node, whether a globalor local synchronous node, would end at the next boundary, such as localsynchronization boundary 906.

Those of skill in the art would understand that information and signalsmay be represented using any of a variety of different technologies andtechniques. For example, data, instructions, commands, information,signals, bits, symbols, and chips that may be referenced throughout theabove description may be represented by voltages, currents,electromagnetic waves, magnetic fields or particles, optical fields orparticles, or any combination thereof.

The functional blocks and modules in FIGS. 7 and 8 may compriseprocessors, electronics devices, hardware devices, electronicscomponents, logical circuits, memories, software codes, firmware codes,etc., or any combination thereof.

Those of skill would further appreciate that the various illustrativelogical blocks, modules, circuits, and algorithm steps described inconnection with the disclosure herein may be implemented as electronichardware, computer software, or combinations of both. To clearlyillustrate this interchangeability of hardware and software, variousillustrative components, blocks, modules, circuits, and steps have beendescribed above generally in terms of their functionality. Whether suchfunctionality is implemented as hardware or software depends upon theparticular application and design constraints imposed on the overallsystem. Skilled artisans may implement the described functionality invarying ways for each particular application, but such implementationdecisions should not be interpreted as causing a departure from thescope of the present disclosure. Skilled artisans will also readilyrecognize that the order or combination of components, methods, orinteractions that are described herein are merely examples and that thecomponents, methods, or interactions of the various aspects of thepresent disclosure may be combined or performed in ways other than thoseillustrated and described herein.

The various aspects of the present disclosure may be implemented in manydifferent ways, including methods, processes, non-transitorycomputer-readable medium having program code recorded thereon, apparatushaving one or more processors with configurations and instructions forperforming the described features and functionality, and the like. Afirst aspect of wireless communication may include selecting, by a firstnode, to access a shared communication channel according to a localsynchronous access mode; performing, by the first node, a LBT procedureon the shared communication channel using a local synchronous energydetection threshold, wherein the local synchronous energy detectionlevel is relaxed relative to a standard energy detection level used foraccess to the shared communication channel; establishing, by the firstnode in response to success of the LBT procedure, a COT configured bythe first node to end at a next synchronization boundary determinedaccording to a local synchronous access clock; and transmitting, by thefirst node, data on the shared communication channel within the COT upto the end at the next synchronization boundary.

In a second aspect, alone or in combination with the first aspect,wherein the LBT procedure is performed by the first node during acontention window at a current synchronization boundary onesynchronization interval prior to the next synchronization boundary.

In a third aspect, alone or in combination with one or more of the firstaspect or the second aspect, wherein the LBT procedure is performed bythe first node after the contention window at the currentsynchronization boundary.

In a fourth aspect, alone or in combination with one or more of thefirst aspect through the third aspect, further including: receiving, atthe first node, a set of synchronization parameters from a neighboringnode to access the shared communication channel according to the localsynchronous access mode, wherein the set of synchronization parametersincludes one or more of a reference to the local synchronous accessclock, a local synchronization boundary reference point, and asynchronization interval, wherein the selecting is in response toreceipt of the set of synchronization parameters, and wherein the nextsynchronization boundary is a function of the local synchronizationboundary reference point and the synchronization interval.

In a fifth aspect, alone or in combination with one or more of the firstaspect through the fourth aspect, wherein the selecting includes:defining, by the first node, a local synchronization boundary referencepoint and a synchronization interval referenced according to the localsynchronization access clock operated by the first node, wherein thenext synchronization boundary is a function of the local synchronizationboundary reference point and the synchronization interval; andsignaling, by the first node, a set of synchronization parameters to oneor more neighboring nodes, wherein the set of synchronization parametersincludes one or more of a reference to the local synchronous accessclock, the local synchronization boundary reference point, and thesynchronization interval.

In a sixth aspect, alone or in combination with one or more of the firstaspect through the fifth aspect, wherein the shared communicationchannel resides within a 6 GHz band.

In a seventh aspect, alone or in combination with one or more of thefirst aspect through the sixth aspect, wherein the standard energydetection level includes one of −72 dBm, −75 dBm, or −80 dBm and thelocal synchronous energy detection level includes one of: −60 dBm, −62dBm, or −65 dBm.

An eighth aspect of wireless communication may include determining, by afirst node configured in a global synchronous access mode, that one ormore neighboring nodes operate in a local synchronous access mode foraccess to a shared communication channel; performing, by the first node,a LBT procedure on the shared communication channel using a localsynchronous energy detection threshold, wherein the local synchronousenergy detection level is relaxed relative to a standard energydetection level used for access to the shared communication channel;establishing, by the first node in response to success of the LBTprocedure, a COT configured by the first node to end at a next localsynchronization boundary determined according to a local synchronousaccess clock; and transmitting, by the first node, data on the sharedcommunication channel within the COT up to the end at the nextsynchronization boundary.

In a ninth aspect, alone or in combination with the eighth aspect,wherein the LBT procedure is performed by the first node during acontention window at a current synchronization boundary onesynchronization interval prior to the next synchronization boundary.

In a tenth aspect, alone or in combination with one or more of theeighth aspect or the ninth aspect, wherein the LBT procedure isperformed by the first node after the contention window at the currentsynchronization boundary.

In an eleventh aspect, alone or in combination with one or more of theeighth aspect through the tenth aspect, further including: receiving, atthe first node, a set of synchronization parameters from a neighboringnode to access the shared communication channel according to the localsynchronous access mode, wherein the set of synchronization parametersincludes one or more of a reference to the local synchronous accessclock, a local synchronization boundary reference point, and asynchronization interval, wherein the selecting is in response toreceipt of the set of synchronization parameters, and wherein the nextsynchronization boundary is a function of the local synchronizationboundary reference point and the synchronization interval.

In a twelfth aspect, alone or in combination with one or more of theeighth aspect through the eleventh aspect, wherein the selectingincludes: defining, by the first node, a local synchronization boundaryreference point and a synchronization interval referenced according tothe local synchronization access clock operated by the first node,wherein the next synchronization boundary is a function of the localsynchronization boundary reference point and the synchronizationinterval; and signaling, by the first node, a set of synchronizationparameters to one or more neighboring nodes, wherein the set ofsynchronization parameters includes one or more of a reference to thelocal synchronous access clock, the local synchronization boundaryreference point, and the synchronization interval.

In a thirteenth aspect, alone or in combination with one or more of theeighth aspect through the twelfth aspect, wherein the sharedcommunication channel resides within a 6 GHz band.

In a fourteenth aspect, alone or in combination with one or more of theeighth aspect through the thirteenth aspect, wherein the standard energydetection level includes one of −72 dBm, −75 dBm, or −80 dBm and thelocal synchronous energy detection level includes one of −60 dBm, −62dBm, or −65 dBm.

A fifteenth aspect configured for wireless communication may include atleast one processor; and a memory coupled to the at least one processor,wherein the at least one processor is configured: to select, by a firstnode, to access a shared communication channel according to a localsynchronous access mode; to perform, by the first node, a LBT procedureon the shared communication channel using a local synchronous energydetection threshold, wherein the local synchronous energy detectionlevel is relaxed relative to a standard energy detection level used foraccess to the shared communication channel; to establish, by the firstnode in response to success of the LBT procedure, a COT configured bythe first node to end at a next synchronization boundary determinedaccording to a local synchronous access clock; and to transmit, by thefirst node, data on the shared communication channel within the COT upto the end at the next synchronization boundary.

In a sixteenth aspect, alone or in combination with the fifteenthaspect, wherein the LBT procedure is performed by the first node duringa contention window at a current synchronization boundary onesynchronization interval prior to the next synchronization boundary.

In a seventeenth aspect, alone or in combination with the fifteenthaspect or the sixteenth aspect, wherein the LBT procedure is performedby the first node after the contention window at the currentsynchronization boundary.

In an eighteenth aspect, alone or in combination with one or more of thefifteenth aspect through the seventeenth aspect, further includingconfiguration of the at least one processor: to receive, at the firstnode, a set of synchronization parameters from a neighboring node toaccess the shared communication channel according to the localsynchronous access mode, wherein the set of synchronization parametersincludes one or more of a reference to the local synchronous accessclock, a local synchronization boundary reference point, and asynchronization interval, wherein the configuration of the at least oneprocessor to select is executed in response to receipt of the set ofsynchronization parameters, and wherein the next synchronizationboundary is a function of the local synchronization boundary referencepoint and the synchronization interval.

In a nineteenth aspect, alone or in combination with one or more of thefifteenth aspect through the eighteenth aspect, wherein theconfiguration of the at least one processor to select includesconfiguration of the at least one processor: to define, by the firstnode, a local synchronization boundary reference point and asynchronization interval referenced according to the localsynchronization access clock operated by the first node, wherein thenext synchronization boundary is a function of the local synchronizationboundary reference point and the synchronization interval; and tosignal, by the first node, a set of synchronization parameters to one ormore neighboring nodes, wherein the set of synchronization parametersincludes one or more of a reference to the local synchronous accessclock, the local synchronization boundary reference point, and thesynchronization interval.

In a twentieth aspect, alone or in combination with one or more of thefifteenth aspect through the nineteenth aspect, wherein the sharedcommunication channel resides within a 6 GHz band.

In a twenty-first aspect, alone or in combination with one or more ofthe fifteenth aspect through the twentieth aspect, wherein the standardenergy detection level includes one of −72 dBm, −75 dBm, or −80 dBm andthe local synchronous energy detection level includes one of −60 dBm,−62 dBm, or −65 dBm.

A twenty-second aspect configured for wireless communication may includeat least one processor; and a memory coupled to the at least oneprocessor, wherein the at least one processor is configured: todetermine, by a first node configured in a global synchronous accessmode, that one or more neighboring nodes operate in a local synchronousaccess mode for access to a shared communication channel; to perform, bythe first node, a LBT procedure on the shared communication channelusing a local synchronous energy detection threshold, wherein the localsynchronous energy detection level is relaxed relative to a standardenergy detection level used for access to the shared communicationchannel; to establish, by the first node in response to success of theLBT procedure, a COT configured by the first node to end at a next localsynchronization boundary determined according to a local synchronousaccess clock; and to transmit, by the first node, data on the sharedcommunication channel within the COT up to the end at the nextsynchronization boundary.

In a twenty-third aspect, alone or in combination with the twenty-secondaspect, wherein the LBT procedure is performed by the first node duringa contention window at a current synchronization boundary onesynchronization interval prior to the next synchronization boundary.

In a twenty-fourth aspect, alone or in combination with one or more ofthe twenty-second aspect and the twenty-third aspect, wherein the LBTprocedure is performed by the first node after the contention window atthe current synchronization boundary.

In a twenty-fifth aspect, alone or in combination with one or more ofthe twenty-second aspect through the twenty-fourth aspect, furtherincluding configuration of the at least one processor: to receive, atthe first node, a set of synchronization parameters from a neighboringnode to access the shared communication channel according to the localsynchronous access mode, wherein the set of synchronization parametersincludes one or more of a reference to the local synchronous accessclock, a local synchronization boundary reference point, and asynchronization interval, wherein the selecting is in response toreceipt of the set of synchronization parameters, and wherein the nextsynchronization boundary is a function of the local synchronizationboundary reference point and the synchronization interval.

In a twenty-sixth aspect, alone or in combination with one or more ofthe twenty-second aspect through the twenty-fifth aspect, wherein theconfiguration of the at least one processor to select includesconfiguration of the at least one processor: to define, by the firstnode, a local synchronization boundary reference point and asynchronization interval referenced according to the localsynchronization access clock operated by the first node, wherein thenext synchronization boundary is a function of the local synchronizationboundary reference point and the synchronization interval; and tosignal, by the first node, a set of synchronization parameters to one ormore neighboring nodes, wherein the set of synchronization parametersincludes one or more of a reference to the local synchronous accessclock, the local synchronization boundary reference point, and thesynchronization interval.

In a twenty-seventh aspect, alone or in combination with one or more ofthe twenty-second aspect through the twenty-sixth aspect, wherein theshared communication channel resides within a 6 GHz band.

In a twenty-eighth aspect, alone or in combination with one or more ofthe twenty-second aspect through the twenty-seventh aspect, wherein thestandard energy detection level includes one of −72 dBm, −75 dBm, or −80dBm and the local synchronous energy detection level includes one of −60dBm, −62 dBm, or −65 dBm.

A twenty-ninth aspect of wireless communication may include means forselecting, by a first node, to access a shared communication channelaccording to a local synchronous access mode; means for performing, bythe first node, a LBT procedure on the shared communication channelusing a local synchronous energy detection threshold, wherein the localsynchronous energy detection level is relaxed relative to a standardenergy detection level used for access to the shared communicationchannel; means for establishing, by the first node in response tosuccess of the LBT procedure, a COT configured by the first node to endat a next synchronization boundary determined according to a localsynchronous access clock; and means for transmitting, by the first node,data on the shared communication channel within the COT up to the end atthe next synchronization boundary.

In a thirtieth aspect, alone or in combination with the twenty-ninthaspect, wherein the LBT procedure is performed by the first node duringa contention window at a current synchronization boundary onesynchronization interval prior to the next synchronization boundary.

In a thirty-first aspect, alone or in combination with one or more ofthe twenty-ninth aspect and the thirtieth aspect, wherein the LBTprocedure is performed by the first node after the contention window atthe current synchronization boundary.

In a thirty-second aspect, alone or in combination with one or more ofthe twenty-ninth aspect through the thirty-first aspect, furtherincluding: means for receiving, at the first node, a set ofsynchronization parameters from a neighboring node to access the sharedcommunication channel according to the local synchronous access mode,means for wherein the set of synchronization parameters includes one ormore of a reference to the local synchronous access clock, a localsynchronization boundary reference point, and a synchronizationinterval, wherein the means for selecting is executed in response toreceipt of the set of synchronization parameters, and wherein the nextsynchronization boundary is a function of the local synchronizationboundary reference point and the synchronization interval.

In a thirty-third aspect, alone or in combination with one or more ofthe twenty-ninth aspect through the thirty-second aspect, wherein themeans for selecting includes: means for defining, by the first node, alocal synchronization boundary reference point and a synchronizationinterval referenced according to the local synchronization access clockoperated by the first node, wherein the next synchronization boundary isa function of the local synchronization boundary reference point and thesynchronization interval; and means for signaling, by the first node, aset of synchronization parameters to one or more neighboring nodes,wherein the set of synchronization parameters includes one or more of areference to the local synchronous access clock, the localsynchronization boundary reference point, and the synchronizationinterval.

In a thirty-fourth aspect, alone or in combination with one or more ofthe twenty-ninth aspect through the thirty-third aspect, wherein theshared communication channel resides within a 6 GHz band.

In a thirty-fifth aspect, alone or in combination with one or more ofthe twenty-ninth aspect through the thirty-fourth aspect, wherein thestandard energy detection level includes one of −72 dBm, −75 dBm, or −80dBm and the local synchronous energy detection level includes one of:−60 dBm, −62 dBm, or −65 dBm.

A thirty-sixth aspect of wireless communication may include means fordetermining, by a first node configured in a global synchronous accessmode, that one or more neighboring nodes operate in a local synchronousaccess mode for access to a shared communication channel; means forperforming, by the first node, a LBT procedure on the sharedcommunication channel using a local synchronous energy detectionthreshold, wherein the local synchronous energy detection level isrelaxed relative to a standard energy detection level used for access tothe shared communication channel; means for establishing, by the firstnode in response to success of the LBT procedure, a COT configured bythe first node to end at a next local synchronization boundarydetermined according to a local synchronous access clock; and means fortransmitting, by the first node, data on the shared communicationchannel within the COT up to the end at the next synchronizationboundary.

In a thirty-seventh aspect, alone or in combination with thethirty-sixth aspect, wherein the LBT procedure is performed by the firstnode during a contention window at a current synchronization boundaryone synchronization interval prior to the next synchronization boundary.

In a thirty-eighth aspect, alone or in combination with one or more ofthe thirty-sixth aspect and the thirty-seventh aspect, wherein the LBTprocedure is performed by the first node after the contention window atthe current synchronization boundary.

In a thirty-ninth aspect, alone or in combination with one or more ofthe thirty-sixth aspect through the thirty-eighth aspect, furtherincluding: means for receiving, at the first node, a set ofsynchronization parameters from a neighboring node to access the sharedcommunication channel according to the local synchronous access mode,wherein the set of synchronization parameters includes one or more of areference to the local synchronous access clock, a local synchronizationboundary reference point, and a synchronization interval, wherein themeans for selecting is executed in response to receipt of the set ofsynchronization parameters, and wherein the next synchronizationboundary is a function of the local synchronization boundary referencepoint and the synchronization interval.

In a fortieth aspect, alone or in combination with one or more of thethirty-sixth aspect through the thirty-ninth aspect, wherein the meansfor selecting includes: means for defining, by the first node, a localsynchronization boundary reference point and a synchronization intervalreferenced according to the local synchronization access clock operatedby the first node, wherein the next synchronization boundary is afunction of the local synchronization boundary reference point and thesynchronization interval; and means for signaling, by the first node, aset of synchronization parameters to one or more neighboring nodes,wherein the set of synchronization parameters includes one or more of areference to the local synchronous access clock, the localsynchronization boundary reference point, and the synchronizationinterval.

In a forty-first aspect, alone or in combination with one or more of thethirty-sixth aspect through the fortieth aspect, wherein the sharedcommunication channel resides within a 6 GHz band.

In a forty-second aspect, alone or in combination with one or more ofthe thirty-sixth aspect through the forty-first aspect, wherein thestandard energy detection level includes one of −72 dBm, −75 dBm, or −80dBm and the local synchronous energy detection level includes one of −60dBm, −62 dBm, or −65 dBm.

A forty-third aspect configured for wireless communication including anon-transitory computer-readable medium having program code recordedthereon, the program code including program code executable by acomputer for causing the computer to select, by a first node, to accessa shared communication channel according to a local synchronous accessmode; program code executable by the computer for causing the computerto perform, by the first node, a LBT procedure on the sharedcommunication channel using a local synchronous energy detectionthreshold, wherein the local synchronous energy detection level isrelaxed relative to a standard energy detection level used for access tothe shared communication channel; program code executable by thecomputer for causing the computer to establish, by the first node inresponse to success of the LBT procedure, a COT configured by the firstnode to end at a next synchronization boundary determined according to alocal synchronous access clock; and program code executable by thecomputer for causing the computer to transmit, by the first node, dataon the shared communication channel within the COT up to the end at thenext synchronization boundary.

In a forty-fourth aspect, alone or in combination with the forty-thirdaspect, wherein the LBT procedure is performed by the first node duringa contention window at a current synchronization boundary onesynchronization interval prior to the next synchronization boundary.

In a forty-fifth aspect, alone or in combination with one or more of theforty-third aspect and the forty-fourth aspect, wherein the LBTprocedure is performed by the first node after the contention window atthe current synchronization boundary.

In a forty-sixth aspect, alone or in combination with one or more of theforty-third aspect through the forty-fifth aspect, further includingprogram code executable by the computer for causing the computer toreceive, at the first node, a set of synchronization parameters from aneighboring node to access the shared communication channel according tothe local synchronous access mode, wherein the set of synchronizationparameters includes one or more of a reference to the local synchronousaccess clock, a local synchronization boundary reference point, and asynchronization interval, wherein the program code executable by thecomputer for causing the computer to select is executed in response toreceipt of the set of synchronization parameters, and wherein the nextsynchronization boundary is a function of the local synchronizationboundary reference point and the synchronization interval.

In a forty-seventh aspect, alone or in combination with one or more ofthe forty-third aspect through the forty-sixth aspect, wherein theprogram code executable by the computer for causing the computer toselect includes program code executable by the computer for causing thecomputer to define, by the first node, a local synchronization boundaryreference point and a synchronization interval referenced according tothe local synchronization access clock operated by the first node,wherein the next synchronization boundary is a function of the localsynchronization boundary reference point and the synchronizationinterval; and program code executable by the computer for causing thecomputer to signal, by the first node, a set of synchronizationparameters to one or more neighboring nodes, wherein the set ofsynchronization parameters includes one or more of a reference to thelocal synchronous access clock, the local synchronization boundaryreference point, and the synchronization interval.

In a forty-eighth aspect, alone or in combination with one or more ofthe forty-third aspect through the forty-seventh aspect, wherein theshared communication channel resides within a 6 GHz band.

In a forty-ninth aspect, alone or in combination with one or more of theforty-third aspect through the forty-eighth aspect, wherein the standardenergy detection level includes one of −72 dBm, −75 dBm, or −80 dBm andthe local synchronous energy detection level includes one of −60 dBm,−62 dBm, or −65 dBm.

A fiftieth aspect configured for wireless communication including anon-transitory computer-readable medium having program code recordedthereon, the program code including program code executable by acomputer for causing the computer to determine, by a first nodeconfigured in a global synchronous access mode, that one or moreneighboring nodes operate in a local synchronous access mode for accessto a shared communication channel; program code executable by thecomputer for causing the computer to perform, by the first node, a LBTprocedure on the shared communication channel using a local synchronousenergy detection threshold, wherein the local synchronous energydetection level is relaxed relative to a standard energy detection levelused for access to the shared communication channel; program codeexecutable by the computer for causing the computer to establish, by thefirst node in response to success of the LBT procedure, a COT configuredby the first node to end at a next local synchronization boundarydetermined according to a local synchronous access clock; and programcode executable by the computer for causing the computer to transmit, bythe first node, data on the shared communication channel within the COTup to the end at the next synchronization boundary.

In a fifty-first aspect, alone or in combination with the fiftiethaspect, wherein the LBT procedure is performed by the first node duringa contention window at a current synchronization boundary onesynchronization interval prior to the next synchronization boundary.

In a fifty-second aspect, alone or in combination with one or more ofthe fiftieth aspect and the fifty-first aspect, wherein the LBTprocedure is performed by the first node after the contention window atthe current synchronization boundary.

In a fifty-third aspect, alone or in combination with one or more of thefiftieth aspect through the fifty-second aspect, further includingprogram code executable by the computer for causing the computer toreceive, at the first node, a set of synchronization parameters from aneighboring node to access the shared communication channel according tothe local synchronous access mode, wherein the set of synchronizationparameters includes one or more of a reference to the local synchronousaccess clock, a local synchronization boundary reference point, and asynchronization interval, wherein the program code executable by thecomputer for causing the computer to select is executed in response toreceipt of the set of synchronization parameters, and wherein the nextsynchronization boundary is a function of the local synchronizationboundary reference point and the synchronization interval.

In a fifty-fourth aspect, alone or in combination with one or more ofthe fiftieth aspect through the fifty-third aspect, wherein the programcode executable by the computer for causing the computer to selectincludes program code executable by the computer for causing thecomputer to define, by the first node, a local synchronization boundaryreference point and a synchronization interval referenced according tothe local synchronization access clock operated by the first node,wherein the next synchronization boundary is a function of the localsynchronization boundary reference point and the synchronizationinterval; and program code executable by the computer for causing thecomputer to signal, by the first node, a set of synchronizationparameters to one or more neighboring nodes, wherein the set ofsynchronization parameters includes one or more of a reference to thelocal synchronous access clock, the local synchronization boundaryreference point, and the synchronization interval.

In a fifty-fifth aspect, alone or in combination with one or more of thefiftieth aspect through the fifty-fourth aspect, wherein the sharedcommunication channel resides within a 6 GHz band.

In a fifty-sixth aspect, alone or in combination with one or more of thefiftieth aspect through the fifty-fifth aspect, wherein the standardenergy detection level includes one of −72 dBm, −75 dBm, or −80 dBm andthe local synchronous energy detection level includes one of −60 dBm,−62 dBm, or −65 dBm.

The various illustrative logical blocks, modules, and circuits describedin connection with the disclosure herein may be implemented or performedwith a general-purpose processor, a digital signal processor (DSP), anapplication specific integrated circuit (ASIC), a field programmablegate array (FPGA) or other programmable logic device, discrete gate ortransistor logic, discrete hardware components, or any combinationthereof designed to perform the functions described herein. Ageneral-purpose processor may be a microprocessor, but in thealternative, the processor may be any conventional processor,controller, microcontroller, or state machine. A processor may also beimplemented as a combination of computing devices, e.g., a combinationof a DSP and a microprocessor, a plurality of microprocessors, one ormore microprocessors in conjunction with a DSP core, or any other suchconfiguration.

The steps of a method or algorithm described in connection with thedisclosure herein may be embodied directly in hardware, in a softwaremodule executed by a processor, or in a combination of the two. Asoftware module may reside in RAM memory, flash memory, ROM memory,EPROM memory, EEPROM memory, registers, hard disk, a removable disk, aCD-ROM, or any other form of storage medium known in the art. Anexemplary storage medium is coupled to the processor such that theprocessor can read information from, and write information to, thestorage medium. In the alternative, the storage medium may be integralto the processor. The processor and the storage medium may reside in anASIC. The ASIC may reside in a user terminal. In the alternative, theprocessor and the storage medium may reside as discrete components in auser terminal.

In one or more exemplary designs, the functions described may beimplemented in hardware, software, firmware, or any combination thereofIf implemented in software, the functions may be stored on ortransmitted over as one or more instructions or code on acomputer-readable medium. Computer-readable media includes both computerstorage media and communication media including any medium thatfacilitates transfer of a computer program from one place to another.Computer-readable storage media may be any available media that can beaccessed by a general purpose or special purpose computer. By way ofexample, and not limitation, such computer-readable media can compriseRAM, ROM, EEPROM, CD-ROM or other optical disk storage, magnetic diskstorage or other magnetic storage devices, or any other medium that canbe used to carry or store desired program code means in the form ofinstructions or data structures and that can be accessed by ageneral-purpose or special-purpose computer, or a general-purpose orspecial-purpose processor. Also, a connection may be properly termed acomputer-readable medium. For example, if the software is transmittedfrom a website, server, or other remote source using a coaxial cable,fiber optic cable, twisted pair, or digital subscriber line (DSL), thenthe coaxial cable, fiber optic cable, twisted pair, or DSL, are includedin the definition of medium. Disk and disc, as used herein, includescompact disc (CD), laser disc, optical disc, digital versatile disc(DVD), floppy disk and blu-ray disc where disks usually reproduce datamagnetically, while discs reproduce data optically with lasers.Combinations of the above should also be included within the scope ofcomputer-readable media.

As used herein, including in the claims, the term “and/or,” when used ina list of two or more items, means that any one of the listed items canbe employed by itself, or any combination of two or more of the listeditems can be employed. For example, if a composition is described ascontaining components A, B, and/or C, the composition can contain Aalone; B alone; C alone; A and B in combination; A and C in combination;B and C in combination; or A, B, and C in combination. Also, as usedherein, including in the claims, “or” as used in a list of itemsprefaced by “at least one of” indicates a disjunctive list such that,for example, a list of “at least one of A, B, or C” means A or B or C orAB or AC or BC or ABC (i.e., A and B and C) or any of these in anycombination thereof.

The previous description of the disclosure is provided to enable anyperson skilled in the art to make or use the disclosure. Variousmodifications to the disclosure will be readily apparent to thoseskilled in the art, and the generic principles defined herein may beapplied to other variations without departing from the spirit or scopeof the disclosure. Thus, the disclosure is not intended to be limited tothe examples and designs described herein but is to be accorded thewidest scope consistent with the principles and novel features disclosedherein.

What is claimed is:
 1. A method of wireless communication, comprising:selecting, by a first node, to access a shared communication channelaccording to a local synchronous access mode; performing, by the firstnode, a listen before talk (LBT) procedure on the shared communicationchannel using a local synchronous energy detection threshold, whereinthe local synchronous energy detection level is relaxed relative to astandard energy detection level used for access to the sharedcommunication channel; establishing, by the first node in response tosuccess of the LBT procedure, a channel occupancy time (COT) configuredby the first node to end at a next synchronization boundary determinedaccording to a local synchronous access clock; and transmitting, by thefirst node, data on the shared communication channel within the COT upto the end at the next synchronization boundary.
 2. The method of claim1, wherein the LBT procedure is performed by the first node during acontention window at a current synchronization boundary onesynchronization interval prior to the next synchronization boundary. 3.The method of claim 1, wherein the LBT procedure is performed by thefirst node after the contention window at the current synchronizationboundary.
 4. The method of claim 1, further including: receiving, at thefirst node, a set of synchronization parameters from a neighboring nodeto access the shared communication channel according to the localsynchronous access mode, wherein the set of synchronization parametersincludes one or more of a reference to the local synchronous accessclock, a local synchronization boundary reference point, and asynchronization interval, wherein the selecting is in response toreceipt of the set of synchronization parameters, and wherein the nextsynchronization boundary is a function of the local synchronizationboundary reference point and the synchronization interval.
 5. The methodof claim 1, wherein the selecting includes: defining, by the first node,a local synchronization boundary reference point and a synchronizationinterval referenced according to the local synchronization access clockoperated by the first node, wherein the next synchronization boundary isa function of the local synchronization boundary reference point and thesynchronization interval; and signaling, by the first node, a set ofsynchronization parameters to one or more neighboring nodes, wherein theset of synchronization parameters includes one or more of a reference tothe local synchronous access clock, the local synchronization boundaryreference point, and the synchronization interval.
 6. The method ofclaim 1, wherein the shared communication channel resides within a 6 GHzband.
 7. The method of claim 1, wherein the standard energy detectionlevel includes one of −72 dBm, −75 dBm, or −80 dBm and the localsynchronous energy detection level includes one of: −60 dBm, −62 dBm, or−65 dBm.
 8. A method of wireless communication, comprising: determining,by a first node configured in a global synchronous access mode, that oneor more neighboring nodes operate in a local synchronous access mode foraccess to a shared communication channel; performing, by the first node,a listen before talk (LBT) procedure on the shared communication channelusing a local synchronous energy detection threshold, wherein the localsynchronous energy detection level is relaxed relative to a standardenergy detection level used for access to the shared communicationchannel; establishing, by the first node in response to success of theLBT procedure, a channel occupancy time (COT) configured by the firstnode to end at a next local synchronization boundary determinedaccording to a local synchronous access clock; and transmitting, by thefirst node, data on the shared communication channel within the COT upto the end at the next synchronization boundary.
 9. The method of claim8, wherein the LBT procedure is performed by the first node during acontention window at a current synchronization boundary onesynchronization interval prior to the next synchronization boundary. 10.The method of claim 8, wherein the LBT procedure is performed by thefirst node after the contention window at the current synchronizationboundary.
 11. The method of claim 8, further including: receiving, atthe first node, a set of synchronization parameters from a neighboringnode to access the shared communication channel according to the localsynchronous access mode, wherein the set of synchronization parametersincludes one or more of a reference to the local synchronous accessclock, a local synchronization boundary reference point, and asynchronization interval, wherein the selecting is in response toreceipt of the set of synchronization parameters, and wherein the nextsynchronization boundary is a function of the local synchronizationboundary reference point and the synchronization interval.
 12. Themethod of claim 8, wherein the selecting includes: defining, by thefirst node, a local synchronization boundary reference point and asynchronization interval referenced according to the localsynchronization access clock operated by the first node, wherein thenext synchronization boundary is a function of the local synchronizationboundary reference point and the synchronization interval; andsignaling, by the first node, a set of synchronization parameters to oneor more neighboring nodes, wherein the set of synchronization parametersincludes one or more of a reference to the local synchronous accessclock, the local synchronization boundary reference point, and thesynchronization interval.
 13. The method of claim 8, wherein the sharedcommunication channel resides within a 6 GHz band.
 14. The method ofclaim 8, wherein the standard energy detection level includes one of −72dBm, −75 dBm, or −80 dBm and the local synchronous energy detectionlevel includes one of −60 dBm, −62 dBm, or −65 dBm.
 15. An apparatusconfigured for wireless communication, the apparatus comprising: atleast one processor; and a memory coupled to the at least one processor,wherein the at least one processor is configured: to select, by a firstnode, to access a shared communication channel according to a localsynchronous access mode; to perform, by the first node, a listen beforetalk (LBT) procedure on the shared communication channel using a localsynchronous energy detection threshold, wherein the local synchronousenergy detection level is relaxed relative to a standard energydetection level used for access to the shared communication channel; toestablish, by the first node in response to success of the LBTprocedure, a channel occupancy time (COT) configured by the first nodeto end at a next synchronization boundary determined according to alocal synchronous access clock; and to transmit, by the first node, dataon the shared communication channel within the COT up to the end at thenext synchronization boundary.
 16. The apparatus of claim 15, whereinthe LBT procedure is performed by the first node during a contentionwindow at a current synchronization boundary one synchronizationinterval prior to the next synchronization boundary.
 17. The apparatusof claim 15, wherein the LBT procedure is performed by the first nodeafter the contention window at the current synchronization boundary. 18.The apparatus of claim 15, further including configuration of the atleast one processor: to receive, at the first node, a set ofsynchronization parameters from a neighboring node to access the sharedcommunication channel according to the local synchronous access mode,wherein the set of synchronization parameters includes one or more of areference to the local synchronous access clock, a local synchronizationboundary reference point, and a synchronization interval, wherein theconfiguration of the at least one processor to select is executed inresponse to receipt of the set of synchronization parameters, andwherein the next synchronization boundary is a function of the localsynchronization boundary reference point and the synchronizationinterval.
 19. The apparatus of claim 15, wherein the configuration ofthe at least one processor to select includes configuration of the atleast one processor: to define, by the first node, a localsynchronization boundary reference point and a synchronization intervalreferenced according to the local synchronization access clock operatedby the first node, wherein the next synchronization boundary is afunction of the local synchronization boundary reference point and thesynchronization interval; and to signal, by the first node, a set ofsynchronization parameters to one or more neighboring nodes, wherein theset of synchronization parameters includes one or more of a reference tothe local synchronous access clock, the local synchronization boundaryreference point, and the synchronization interval.
 20. The apparatus ofclaim 15, wherein the shared communication channel resides within a 6GHz band.
 21. The apparatus of claim 15, wherein the standard energydetection level includes one of −72 dBm, −75 dBm, or −80 dBm and thelocal synchronous energy detection level includes one of −60 dBm, −62dBm, or −65 dBm.
 22. An apparatus configured for wireless communication,the apparatus comprising: at least one processor; and a memory coupledto the at least one processor, wherein the at least one processor isconfigured: to determine, by a first node configured in a globalsynchronous access mode, that one or more neighboring nodes operate in alocal synchronous access mode for access to a shared communicationchannel; to perform, by the first node, a listen before talk (LBT)procedure on the shared communication channel using a local synchronousenergy detection threshold, wherein the local synchronous energydetection level is relaxed relative to a standard energy detection levelused for access to the shared communication channel; to establish, bythe first node in response to success of the LBT procedure, a channeloccupancy time (COT) configured by the first node to end at a next localsynchronization boundary determined according to a local synchronousaccess clock; and to transmit, by the first node, data on the sharedcommunication channel within the COT up to the end at the nextsynchronization boundary.
 23. The apparatus of claim 22, wherein the LBTprocedure is performed by the first node during a contention window at acurrent synchronization boundary one synchronization interval prior tothe next synchronization boundary.
 24. The apparatus of claim 22,wherein the LBT procedure is performed by the first node after thecontention window at the current synchronization boundary.
 25. Theapparatus of claim 22, further including configuration of the at leastone processor: to receive, at the first node, a set of synchronizationparameters from a neighboring node to access the shared communicationchannel according to the local synchronous access mode, wherein the setof synchronization parameters includes one or more of a reference to thelocal synchronous access clock, a local synchronization boundaryreference point, and a synchronization interval, wherein the selectingis in response to receipt of the set of synchronization parameters, andwherein the next synchronization boundary is a function of the localsynchronization boundary reference point and the synchronizationinterval.
 26. The apparatus of claim 22, wherein the configuration ofthe at least one processor to select includes configuration of the atleast one processor: to define, by the first node, a localsynchronization boundary reference point and a synchronization intervalreferenced according to the local synchronization access clock operatedby the first node, wherein the next synchronization boundary is afunction of the local synchronization boundary reference point and thesynchronization interval; and to signal, by the first node, a set ofsynchronization parameters to one or more neighboring nodes, wherein theset of synchronization parameters includes one or more of a reference tothe local synchronous access clock, the local synchronization boundaryreference point, and the synchronization interval.
 27. The method ofclaim 22, wherein the shared communication channel resides within a 6GHz band.
 28. The method of claim 22, wherein the standard energydetection level includes one of −72 dBm, −75 dBm, or −80 dBm and thelocal synchronous energy detection level includes one of −60 dBm, −62dBm, or −65 dBm.